JP2015115614A - Conversion processing method, inverse conversion processing method, conversion processing device, inverse conversion processing device, conversion processing program, and inverse conversion processing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a decoded video of higher quality with less amount of code by enhancing power deviation of residual signals after conversion.SOLUTION: When a target block to be encoded is processed by intra-prediction encoding, a conversion processing method includes: a conversion selection step of selecting a vertically/horizontally non-separated conversion that is applied to a predictive residual signal according to an intra-prediction mode from among a plurality of vertically/horizontally non-separated conversions prepared beforehand; and a conversion step of generating a conversion coefficient by applying the selected vertically/horizontally non-separated conversion to the predictive residual signal. When encoded data to be decoded is processed by intra-prediction encoding, an inverse conversion processing method includes: an inverse conversion selection step of selecting a vertically/horizontally non-separated inverse conversion that is applied to a decoding conversion coefficient according to an intra-prediction mode from among a plurality of vertically/horizontally non-separated inverse conversions prepared beforehand; and an inverse conversion step of generating a predictive residual decoded signal by applying the selected vertically/horizontally non-separated inverse conversion to the decoding conversion coefficient.

Description

  The present invention relates to a conversion processing method, an inverse conversion processing method, a conversion processing device, an inverse conversion processing device, a conversion processing program, and an inverse conversion for improving video quality and reducing an encoding bit rate in lossy encoding of an image / video. It relates to a processing program.

  Conventionally, one of the components of video coding such as HEVC (High Efficiency Video Coding) is called “conversion”. This has the effect of reducing the correlation between pixels included in the residual image after pixel value prediction. The pixel value prediction and conversion in HEVC is performed in units of blocks such as 4 × 4 or 8 × 8 pixels. In image coding, discrete cosine transform (DCT) is widely used as transform. For this, there is a calculation method (high-speed calculation) that is faster than a simple calculation of conversion. JPEG, MPEG-2, H.264, and other international standards for image / video coding. H.264 / AVC uses DCT as a conversion.

  Further, in addition to DCT, HEVC uses a discrete sine transform (DST) in blocks that are intra (in-screen) predictive encoded with a 4 × 4 pixel size. There is also Karhunen-Loeve Transform (KLT), which has the highest ability to reduce the correlation between pixels, and therefore has the highest coding efficiency, but the conversion formula is different for each image (thus, the conversion coefficient information is included in the compressed bitstream, or It is created from a plurality of images in advance), and since there is no high-speed algorithm, there are fewer scenes used than DCT.

  Intra prediction will be described with reference to FIG. FIG. 3 is a diagram illustrating an example of a reference pixel and a predicted block in intra pixel value prediction. Each pixel (indicated by a white circle) in a block surrounded by a square (4 × 4 size in this example) is replaced with reference to the value of a decoded pixel (indicated by a hatched circle) in the vicinity of this block. In this example, the upper left pixel value is referred to.

  Next, intra prediction encoding in HEVC will be described with reference to FIG. FIG. 4 is a diagram illustrating an example of intra prediction mode numbers, corresponding prediction directions (numbers 2 to 35), and non-directional predictions (numbers 0 and 1). In general, it is possible to refer to decoded pixel values along various directions (33 directions), and a direction in which the encoding efficiency is most enhanced is transmitted. In addition to the directional prediction, there are a method (referred to as DC prediction) that uses an average value of peripheral decoded pixel values as a predicted value, and a prediction method that performs interpolation prediction from decoded pixel values (referred to as Planar prediction). The 35 kinds of prediction methods are called “intra prediction mode”. In HEVC, this intra prediction mode is transmitted for each intra prediction block.

A block for which a prediction value is obtained by intra or inter (inter-screen) prediction is filled with a difference from the value of the original pixel at the same position, that is, a prediction error. That is, assuming that the prediction value is P [x, y] and the original pixel value is I [x, y], the prediction error value R [x, y] is R [x, y] = I [x, y] −P [ x, y]
However, x and y are two-dimensional coordinate values in the block.

  Next, prediction error conversion will be described with reference to FIG. FIG. 5 is a diagram illustrating an example of vertical / horizontal separation type conversion of a residual signal using a 4 × 4 block as an example. In this example, first, four points are converted in the horizontal direction for each row. Thus, the power is biased toward the low frequency conversion coefficient (left side of the block). Four columns of conversion are performed in the vertical direction for each column of the obtained conversion coefficients. Thus, the power is biased toward the low-frequency conversion coefficient (upper block side). Thus, the power of the block is biased to the upper left of the block while the sum remains unchanged before and after conversion. This bias contributes to the improvement of the compression rate. The same DCT is often used for both vertical conversion and horizontal conversion. Further, conversion may be performed in the order of the vertical direction first and then the horizontal direction.

  This method of converting the vertical and horizontal separately is called “vertical and horizontal separation type” conversion, and all current video coding international standards use separation type conversion. Examples of the prior art relating to image coding with improved conversion include the following. Non-Patent Document 1 and Non-Patent Document 2 are methods for selecting one of predetermined transformations according to the intra prediction mode. Non-Patent Document 3 performs transformation (Rotational Transform, ROT) combining plane (two-dimensional) rotation in order to reduce the amount of calculation instead of DCT or the like. Non-Patent Document 4 describes KLT or DCT, which is a transform with the highest power concentration degree, according to specific conditions (even or odd of the intra-block quantized transform coefficient sum, transform block size or additionally transmitted flag value). Is selected as the conversion. Similarly, Non-Patent Document 5 uses a method called Multiple Model KLT (MMKLT) in which KLTs prepared in advance under specific conditions are switched. These conversions are all “vertical and horizontal separation type” conversions.

  FIG. 6 is a diagram illustrating an example of vertical / horizontal non-separation conversion of a residual signal taking a 4 × 4 block as an example. As shown in FIG. 6, it is possible to perform the 16-point conversion only once. This is called “vertical and horizontal non-separable” conversion. It is known that the conversion with a large number of points increases the bias in power than the conversion with a small number of points. Efficiency can be further increased. In addition, since the number of filter points is large and the degree of freedom in design is high, power concentration can be increased even for image edges with diagonal edges and striped patterns.

Note that the “inverse conversion” of the vertical / horizontal non-separation type conversion is essentially the same as the reverse conversion of the vertical / horizontal separation type conversion. Since orthogonal transforms (derivations such as KLT, DCT, and MMKLT are categories of orthogonal transforms) are usually used as transforms, when the encoding loop and the decoder perform “inverse transform” of the vertical / horizontal non-separable transform, Inverse transformation is a transpose of the matrix for transformation. That is, it is not necessary to secure an extra storage area for the inverse conversion. This can be expressed as follows: When the block to be converted is a vertical vector x (16 pixel values are arranged vertically if the size is 4 × 4) and the orthogonal transformation matrix is T, the conversion is c = Tx
It becomes. The conversion coefficient c is a vertical vector having the same size as x. At this time, the inverse transformation is x = T′c
It becomes. T ′ is a matrix obtained by transposing T. Thus, if there is information for conversion, a separate storage area for reverse conversion is not necessary.

  These various conversions convert the prediction error signal so as to increase the power bias. If the power is biased, the amount of information decreases, so that less information needs to be transmitted, which contributes to improvement of video coding efficiency.

Y. Ye and M. Karczewicz, "Improved H.264 intra coding based on bi-directional intra prediction, directional transform, and adaptive coefficient scanning," Proc. IEEE ICIP2008, pp. 2116-2119, Oct. 2008. W. Ding, Y. Shi and B. Yin, "Fast mode dependent directional transform via butterfly-style transform and integer lifting steps", JCTVC-B073, 2nd Joint Collaborative Team on Video Coding (JCT-VC) Meeting, July 2010. F. Fernandes, "Low-complexity rotational transform", JCTVC-C096, 3rd Joint Collaborative Team on Video Coding (JCT-VC) Meeting, Oct. 2010. I. Amonou, N. Cammas, G. Clare, J. Jung, L. Noblet, S. Pateux, S. Matsuo, S. Takamura, C. Boon, F. Bossen, A. Fujibayashi, S. Kanumuri, Y. Suzuki, J. Takiue, TK Tan, V. Drugeon, C. Lim, M. Narroschke, T. Nishi, H. Sasai, Y. Shibahara, K. Uchibayashi, T. Wedi, S. Wittmann, P. Bordes, C Gomila, P. Guillotel, L. Guo, E. Francois, X. Lu, J. Sole, J. Vieron, Q. Xu, P. Yin, Y. Zheng, "ideo coding technology proposal by France Telecom, NTT, NTT DoCoMo, Panasonic and Technicolor ", JCTVC-A114, 1st Joint Collaborative Team on Video Coding (JCT-VC) Meeting, Apr. 2010. Y. Huang, C. Fu, Y. Tsai, J. Lin, Y. Chang, J. Guo, C. Chen, S. Lei, X. Guo, Y. Gao, K. Zhang, J. An, "A technical description of MediaTek's proposal to the JCT-VC CfP ", JCTVC-A109, 1st Joint Collaborative Team on Video Coding (JCT-VC) Meeting, Apr. 2010.

  The conversion according to the prior art is “vertical / horizontal separation type” conversion as in the case of the conventional international coding standard. The horizontal stripe pattern or edge can be effectively biased by horizontal conversion, and the vertical stripe pattern or edge can be converted vertically by vertical conversion. However, since the power cannot be effectively biased against the diagonal stripes or edges, there is a problem that a higher quality decoded video cannot be obtained with a smaller code amount.

  In addition, vertical / horizontal non-separation conversion according to the prior art does not switch between multiple conversions according to the direction of the stripes and edges of the image, so the power is most biased with respect to each of the stripes and edges in various directions. It is not something that can be done.

  The present invention has been made in view of such circumstances, and a conversion processing method and inverse conversion that can increase power bias after conversion of a residual signal and obtain a higher quality decoded video with a smaller code amount. It is an object to provide a processing method, a conversion processing device, an inverse conversion processing device, a conversion processing program, and an inverse conversion processing program.

  The present invention is a transform processing method for generating transform coefficients from a prediction residual signal when generating encoded data by predictive encoding of a target block, and the target block to be encoded is intra prediction encoded. Conversion selection step of selecting a vertical / horizontal non-separable transformation to be applied to a prediction residual signal according to an intra prediction mode from a plurality of vertical / horizontal non-separable transformations prepared in advance, A transforming step of generating the transform coefficient by applying the selected vertical / horizontal non-separable transform to the prediction residual signal.

  The present invention is an inverse transform processing method for generating a prediction residual decoded signal from decoded transform coefficients when an image is decoded from encoded data generated by predictive encoding of a target block, and the code to be decoded Vertical / horizontal non-separable inverse transform to be applied to decoded transform coefficients according to the intra prediction mode from a plurality of vertical / horizontal non-separable inverse transforms prepared in advance when the encoded data is processed by intra prediction encoding And an inverse transform step of generating the prediction residual decoded signal by applying the selected vertical / horizontal non-separable inverse transform to the decoded transform coefficients.

  The present invention is a transform processing apparatus that generates transform coefficients from a prediction residual signal when generating encoded data by predictive encoding of a target block, and the target block to be encoded is intra prediction encoded. Conversion processing means for selecting a vertical / horizontal non-separable transformation to be applied to a prediction residual signal according to an intra prediction mode from a plurality of vertical / horizontal non-separable transformations prepared in advance, Conversion means for generating the conversion coefficient by applying the selected vertical / horizontal non-separable conversion to the prediction residual signal.

  The present invention is an inverse transform processing device that generates a prediction residual decoded signal from decoded transform coefficients when an image is decoded from encoded data generated by predictive encoding of a target block, and the code to be decoded Vertical / horizontal non-separable inverse transform to be applied to decoded transform coefficients according to the intra prediction mode from a plurality of vertical / horizontal non-separable inverse transforms prepared in advance when the encoded data is processed by intra prediction encoding And inverse transform means for applying the selected vertical / horizontal non-separated inverse transform to the decoded transform coefficients to generate the prediction residual decoded signal.

  The present invention is a conversion processing program for causing a computer to execute the conversion processing method.

  The present invention is an inverse transformation processing program for causing a computer to execute the inverse transformation processing method.

  According to the present invention, since the quality of a reference image can be improved in an intra prediction coding block, an effect that a decoded video with higher quality can be obtained with a smaller code amount can be obtained.

It is a block diagram which shows the structure of the image coding apparatus containing the conversion process part in one Embodiment of this invention. It is a block diagram which shows the structure of the image decoding apparatus containing the inverse transformation process part by one Embodiment of this invention. It is a figure which shows the example of the reference pixel and to-be-predicted block in intra pixel value prediction. It is a figure which shows the example of an intra prediction mode number, the corresponding prediction direction (numbers 2-35), and non-directional prediction (number 0 and 1). It is a figure which shows the example of the vertical / horizontal separation type | mold conversion of the residual signal which made a 4x4 block an example. It is a figure which shows the example of the vertical / horizontal non-separation type | mold conversion of the residual signal which made a 4x4 block an example.

  Hereinafter, an image encoding device including a conversion processing unit and an inverse conversion processing unit according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an image encoding device including a conversion processing unit and an inverse conversion processing unit in the same embodiment. This image encoding apparatus receives an input image signal of an encoding target image, divides the frame of the input image signal into blocks, encodes each block, and outputs the encoded data as encoded data. In the image encoding apparatus shown in FIG. 1, the conversion processing unit 104 and the inverse conversion processing unit 107 refer to the intra prediction information output from the intra prediction processing unit 101. H.264 / AVC and HEVC are different from each other. The configuration is the same as that of a general image encoding device used as an H.264 / AVC, HEVC, or other image encoding device.

  The prediction residual signal generation unit 103 obtains a difference between the input image signal and the prediction signal output from the inter prediction processing unit 102 or the intra prediction processing unit 101, and outputs the difference as a prediction residual signal. If the prediction residual signal is an inter-predicted block, the transform processing unit 104 performs vertical / horizontal separation type conversion using normal DCT or the like, as in HEVC, and the intra-predicted block is intra-predicted. A vertical / horizontal non-separable conversion based on the intra prediction information output from the processing unit 101 is performed, and a conversion coefficient is output.

  In addition, when it is predicted that an edge in the horizontal direction or the vertical direction is included (intra prediction mode numbers 10 and 26 in HEVC, respectively), or when it is predicted that no significant directionality is included (intra prediction in HEVC). When the mode number is 0 or 1), vertical / horizontal separation type conversion by normal DCT or the like may be performed. Also, when the image signal is stationary (for example, a computer graphics image that is not a natural image. This determination is made when the variance of the decoded pixel values in the vicinity of the encoded block is smaller than a separately specified value. It is also possible to perform vertical / horizontal separation type conversion by ordinary DCT or the like.

  The quantization processing unit 105 quantizes the transform coefficient and outputs a value after quantization. The inverse quantization processing unit 106 receives the quantized transform coefficient and performs an inverse quantization process. The inverse transform processing unit 107 performs vertical / horizontal separation type inverse transform by inverse DCT or the like similar to HEVC or the like if it is an inter-predicted block for the transform coefficient after inverse quantization which is the output of the inverse quantization processing unit 106. If the block is intra-predicted, vertical / horizontal non-separation type inverse transform based on the intra prediction information output from the intra prediction processing unit 101 is performed, and a prediction residual decoded signal is output.

  Also, the inverse transform processing unit 107 is expected to include no horizontal direction or vertical direction edge (in the case of HEVC, the intra prediction mode numbers are 10 and 26, respectively) or not to include significant directionality. (Intra prediction mode number is 0 or 1 in HEVC), vertical / horizontal separation type inverse transform by normal DCT or the like may be performed. In addition, when the image signal is stationary (in the case of a computer graphics image that is not a natural image, the determination is made when the variance of the decoded pixel values in the vicinity of the coding block is smaller than a separately specified value). It is also possible to perform vertical / horizontal separation type inverse transformation by normal DCT or the like. Such exception processing is performed in combination with exception processing performed in the conversion processing unit 104.

  The decoded signal generation unit 108 adds the prediction residual decoded signal and the prediction signal output from the inter prediction processing unit 102 or the intra prediction processing unit 101, and generates a decoded signal of the encoded target block. This decoded signal is stored in the frame memory 109 for use as a reference image in the intra prediction processing unit 101. The intra prediction processing unit 101 sets a prediction mode or the like from the image stored in the frame memory 109. Further, for reference in the inter prediction processing unit 102, the in-loop filter processing unit 110 inputs an image stored in the frame memory 109, performs a filtering process to reduce coding distortion, and stores it in the frame memory 115. .

  The inter prediction processing unit 102 obtains information such as a motion vector and a motion unit from the past image stored in the frame memory 115 and the current input image signal. Information such as prediction coefficients set in the in-loop filter processing unit 110 is stored in the in-loop filter information storage unit 114. Information such as the intra prediction mode set in the intra prediction processing unit 101 is stored in the intra prediction information storage unit 112. The entropy encoding processing unit 113 is an output of the quantization processing unit 105, information such as a post-quantization transform coefficient, a prediction coefficient stored in the in-loop filter information storage unit 114, and an inter prediction information storage unit 111. Information such as a motion vector and information such as a prediction mode stored in the intra prediction information storage unit 112 are entropy-encoded and output as encoded data.

  Next, an image decoding apparatus including an inverse transform processing unit according to an embodiment of the present invention will be described. FIG. 2 is a block diagram showing a configuration of an image decoding apparatus including an inverse transform processing unit in the same embodiment. This image decoding apparatus outputs a video signal of a decoded image by inputting and decoding the encoded data encoded by the image encoding apparatus shown in FIG. In the image decoding apparatus shown in FIG. 2, the inverse transformation processing unit 205 refers to the intra prediction information stored in the intra prediction information storage unit 210. H.264 / AVC and HEVC are different from each other. The configuration is the same as that of a general image decoding apparatus used as an H.264 / AVC, HEVC, or other image encoding apparatus.

  In order to perform decoding, the entropy decoding processing unit 201 inputs encoded data, entropy-decodes the quantized transform coefficient of the block to be decoded, and decodes information related to intra prediction, inter prediction, and in-loop filter, The intra prediction information storage unit 210, the inter prediction information storage unit 209, and the in-loop filter information storage unit 211 respectively store the information. The inverse quantization processing unit 204 inputs the quantized transform coefficient, inversely quantizes it, and outputs a decoded transform coefficient.

  The inverse transform processing unit 205 performs vertical / horizontal separation type inverse transform by inverse DCT or the like similar to HEVC or the like if the block is an inter-predicted block with respect to the transform coefficient after inverse quantization that is the output of the inverse quantization processing unit 204. If the block is intra-predicted, vertical / horizontal non-separation type inverse transform based on the intra prediction information is performed, and a prediction residual decoded signal is output. In addition, the inverse transform processing unit 205 is expected to include no horizontal direction or vertical direction edge (in the case of HEVC, the intra prediction mode numbers are 10 and 26, respectively) or not to include significant directionality. (Intra prediction mode number is 0 or 1 in HEVC), vertical / horizontal separation type inverse transform by normal DCT or the like may be performed.

  In addition, when the image signal is stationary (in the case of a computer graphics image that is not a natural image, the determination is made when the variance of the decoded pixel values in the vicinity of the coding block is smaller than a separately specified value). It is also possible to perform vertical / horizontal separation type inverse transformation by normal DCT or the like. Such exception processing is performed in combination with exception processing in the conversion processing unit 104 (FIG. 1) of the image encoding device. The prediction residual decoded signal and the prediction signal output from the inter prediction processing unit 203 or the intra prediction processing unit 202 are added to generate a decoded signal of the decoding target block. This decoded signal is stored in the frame memory 207 for use as a reference image in the intra prediction processing unit 202.

  Further, in order to refer to the inter prediction processing unit 203, an in-loop filter processing unit 208 inputs an image stored in the frame memory 207, performs a filtering process to reduce coding distortion, and outputs it as an output signal. At the same time, it is stored in the frame memory 206. The in-loop filter processing unit 208 decodes the image quality improvement filter, uses the obtained image quality improvement filter, generates a filtered pixel value, and outputs it as an output signal.

  As described above, the image coding apparatus and the image decoding apparatus according to the present embodiment can predict the direction in which the stripe pattern or the edge of the prediction residual signal is directed for the block subjected to intra prediction coding. It is assumed that vertical and horizontal non-separated KLTs are created in advance according to the direction. Specifically, in HEVC intra-prediction encoding, pre-created vertical / horizontal non-separation conversion is used for x if the intra prediction mode number of the conversion target block is x, and y for y. Since the striped pattern corresponding to the direction of intra prediction is also generated in the prediction residual signal, it is difficult to bias the power with vertical and horizontal separation type conversion. Power can be biased. Therefore, the encoding efficiency can be improved compared to a method of performing normal vertical / horizontal separation type conversion or a method of selecting vertical / horizontal separation type conversion according to the intra prediction mode as in Non-Patent Document 1 and Non-Patent Document 2. it can.

  In this way, by preparing vertical and horizontal non-separated KLTs according to the intra prediction mode, it is possible to increase the power bias after conversion of the residual signal and obtain a higher quality decoded video with a smaller code amount. .

  You may make it implement | achieve the image coding apparatus and image decoding apparatus in embodiment mentioned above with a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory inside a computer system serving as a server or a client in that case may be included and a program held for a certain period of time. Further, the program may be for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in the computer system. It may be realized using hardware such as PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array).

  As mentioned above, although embodiment of this invention has been described with reference to drawings, the said embodiment is only the illustration of this invention, and it is clear that this invention is not limited to the said embodiment. is there. Therefore, additions, omissions, substitutions, and other modifications of the components may be made without departing from the technical idea and scope of the present invention.

    In lossy encoding of images / videos, the present invention can be applied to applications where it is essential to encode / decode images for the purpose of improving video quality and reducing the encoding bit rate.

  DESCRIPTION OF SYMBOLS 101 ... Intra prediction process part, 102 ... Inter prediction process part, 103 ... Prediction residual signal generation part, 104 ... Transformation process part, 105 ... Quantization process part, 106 ... Inverse quantization processing unit, 107 ... Inverse transformation processing unit, 108 ... Decoded signal generation unit, 109 ... Frame memory, 110 ... In-loop filter processing unit, 111 ... Inter prediction information storage unit 112 ... Intra prediction information storage unit, 113 ... Entropy encoding processing unit, 114 ... In-loop filter information storage unit, 115 ... Frame memory, 201 ... Entropy decoding processing unit, 202 .. Intra prediction processing unit, 203 ... Inter prediction processing unit, 204 ... Inverse quantization processing unit, 205 ... Inverse transformation processing unit, 206 ... Frame memory, 207 ... Mumemori, 208 ... loop filter processor, 209 ... inter prediction information storage unit, 210 ... intra-prediction information storage unit, 211 ... loop filter information storage unit

Claims (6)

When generating encoded data by predictive encoding of a target block, a conversion processing method for generating a conversion coefficient from a prediction residual signal,
When the target block to be encoded is processed by intra prediction encoding, the vertical and horizontal are applied to the prediction residual signal according to the intra prediction mode from among a plurality of vertical and horizontal non-separable conversions prepared in advance. A transformation selection step for selecting a non-separable transformation;
A conversion step of applying the selected vertical / horizontal non-separable conversion to the prediction residual signal to generate the conversion coefficient. When an image is decoded from encoded data generated by predictive encoding of a target block, an inverse transform processing method for generating a prediction residual decoded signal from decoded transform coefficients,
When the encoded data to be decoded has been processed by intra prediction encoding, it is applied to decoding transform coefficients according to the intra prediction mode from among a plurality of vertical and horizontal non-separable inverse transforms prepared in advance. Inverse transform selection step for selecting vertical / horizontal non-separable inverse transform,
An inverse transform step of applying the selected vertical / horizontal non-separable inverse transform to the decoded transform coefficient to generate the prediction residual decoded signal. A transform processing device that generates transform coefficients from a prediction residual signal when generating encoded data by predictive encoding of a target block;
When the target block to be encoded is processed by intra prediction encoding, the vertical and horizontal are applied to the prediction residual signal according to the intra prediction mode from among a plurality of vertical and horizontal non-separable conversions prepared in advance. A transformation selection means for selecting a non-separable transformation;
A conversion processing apparatus comprising: conversion means for applying the selected vertical / horizontal non-separable conversion to the prediction residual signal to generate the conversion coefficient. An inverse transform processing device that generates a prediction residual decoded signal from decoded transform coefficients when an image is decoded from encoded data generated by predictive encoding of a target block,
When the encoded data to be decoded has been processed by intra prediction encoding, it is applied to decoding transform coefficients according to the intra prediction mode from among a plurality of vertical and horizontal non-separable inverse transforms prepared in advance. Inverse transform selection means for selecting vertical / horizontal non-separable inverse transform,
Inverse transform processing apparatus, comprising: inverse transform means that applies the selected vertical / horizontal non-separate inverse transform to the decoded transform coefficients to generate the prediction residual decoded signal.   A conversion processing program for causing a computer to execute the conversion processing method according to claim 1.   An inverse transformation processing program for causing a computer to execute the inverse transformation processing method according to claim 2.

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