Mesh decoding device, mesh encoding device, mesh decoding method, and program product

Abstract

A displacement amount decoding unit (206) of a mesh decoding device (200) according to the present invention has: an arithmetic decoding unit (206B) configured so as to generate a binarized syntax by arithmetically decoding a displacement amount bit stream; a context value update unit (206C) configured so as to update the context value using the binarization syntax; a context selection unit (206E) configured to generate a context value for output using the context value read from the context buffer (206D), the position of the bit, and the syntax; a multi-system unit (206F) configured to binarize the syntax by multi-system, generate a syntax, and output the syntax to a context buffer (206D); and a coefficient level value decoding unit (206F2) configured so as to generate a coefficient level value in accordance with a syntax.

Description

Technical Field

[0001] The present invention relates to a grid decoding device, a grid encoding device, a grid decoding method and a program product. Background Art

[0002] A technique for encoding a mesh using non-patent document 2 is disclosed in AnchorSoft of non-patent document 1.

[0003] Prior art literature

[0004] Non-patent literature

[0005] Non-patent literature 1: Cfp for Dynamic Mesh Coding, ISO / IECJTC1 / SC29 / WG7 N00231, MPEG136-Online

[0006] Non-patent document 2: Google Draco, accessed on May 26, 2022 [Online], https: / / google.github.io / draco Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, in the anchoring software of non-patent document 1, since the original grid data is encoded after being simplified, there is a problem of poor encoding performance. Therefore, the present invention is made in view of the above-mentioned problems, and its purpose is to provide a grid decoding device, a grid encoding device, a grid decoding method and a program product that can improve the coding efficiency of the grid.

[0009] Means for solving problems

[0010] The first technical solution of the present invention is a grid decoding device, the main purpose of which is to have: a displacement decoding unit, which is configured to decode the displacement bit stream to generate and output the displacement, and the displacement decoding unit has: an arithmetic decoding unit, which is configured to generate a binarized syntax by arithmetically decoding the displacement bit stream; a context value updating unit, which is configured to update the context value using the binarized syntax; a context buffer, which is configured to obtain and accumulate the context value, bit position and syntax; a context selection unit, which is configured to generate an output context value using the context value, bit position and syntax read from the context buffer; a multi-numbering unit, which is configured to generate syntax by multi-numbering the binarized syntax and output it to the context buffer; a coefficient level value decoding unit, which is configured to generate a coefficient level value according to the syntax; an inverse quantization unit, which is configured to generate a transform coefficient by inverse quantizing the coefficient level value; and an inverse wavelet transform unit, which is configured to generate a prediction residual by performing an inverse wavelet transform on the transform coefficient.

[0011] The second technical solution of the present invention is a grid decoding method, the main purpose of which is to have a process of decoding a displacement bit stream to generate and output a displacement, and the process includes: a process of generating a binarized syntax by arithmetically decoding the displacement bit stream; a process of updating a context value using the binarized syntax; a process of obtaining the context value, bit position and syntax and accumulating them in a context buffer; a process of generating an output context value using the context value, bit position and syntax read from the context buffer; a process of generating syntax by multi-coding the binarized syntax and outputting it to the context buffer; a process of generating a coefficient level value according to the syntax; a process of generating a transform coefficient by inverse quantizing the coefficient level value; and a process of generating a prediction residual by performing an inverse wavelet transform on the transform coefficient.

[0012] The third technical solution of the present invention is a program product, which includes a program that enables a computer to function as a grid decoding device. The main purpose of the program product is that the grid decoding device has: a displacement decoding unit, which is configured to decode the displacement bit stream to generate and output the displacement, and the displacement decoding unit has: an arithmetic decoding unit, which is configured to generate a binary syntax by arithmetically decoding the displacement bit stream; a context value updating unit, which is configured to use the binarized syntax to update the context value; a context buffer, which is configured to obtain and accumulate the context value, bit position and syntax; a context selection unit, which is configured to generate an output context value using the context value read from the context buffer, the bit position and the syntax; a multi-byte unit, which is configured to generate syntax by multi-byteing the binarized syntax and output it to the context buffer; a coefficient level value decoding unit, which is configured to generate coefficient level values ​​according to the syntax; an inverse quantization unit, which is configured to generate transform coefficients by inverse quantizing the coefficient level values; and an inverse wavelet transform unit, which is configured to generate a prediction residual by performing an inverse wavelet transform on the transform coefficients.

[0013] Effects of the Invention

[0014] According to the present invention, a grid decoding device, a grid encoding device, a grid decoding method and a program product that can improve the coding efficiency of the grid can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a diagram showing an example of the configuration of a mesh processing system 1 according to an embodiment.

[0016] Figure 2 This is a diagram showing an example of functional blocks of a trellis decoding device 200 according to an embodiment.

[0017] Figure 3 1 is a diagram showing an example of a functional block of the displacement amount decoding unit 206 of the trellis decoding device 200 according to an embodiment.

[0018] Figure 4 This is a diagram showing an example of a syntactic structure.

[0019] Figure 5 This is a diagram showing prefix code strings and suffix code strings when the maximum value is 32.

[0020] Figure 6 is a diagram showing the prefix code string and the suffix code string of the k-th order Exponential Golomb code.

[0021] Figure 7 This is a diagram showing a specific example of a syntactic structure.

[0022] Figure 8 This is a diagram showing a specific example of a syntactic structure.

[0023] Fig. 9 This is a diagram for explaining the operation of the context selection unit 206E of the trellis decoding device 200 according to one embodiment.

[0024] Fig.10 This is a diagram for explaining the operation of the context selection unit 206E of the trellis decoding device 200 according to one embodiment.

[0025] Fig.11 This is a diagram for explaining the operation of the context selection unit 206E of the trellis decoding device 200 according to one embodiment.

[0026] Fig.12 It is a flowchart showing an example of the operation of the coefficient level value decoding unit 206F2.

[0027] Fig.13 This is a flowchart showing an example of the operations of the arithmetic decoding unit 206B, the context selection unit 206E, the context value updating unit 206C, and the multi-numbering unit 206F.

[0028] Fig.14 This is a diagram for explaining an example of the structure of a bit stream of a displacement amount.

[0029] Explanation of symbols

[0030] 1: Grid processing system;

[0031] 100: grid encoding device;

[0032] 200: grid decoding unit;

[0033] 201: multiplexing and separation unit;

[0034] 202: basic grid decoding unit;

[0035] 203: sub-division part;

[0036] 204: grid decoding unit;

[0037] 205: Patch Integration Department;

[0038] 206: displacement decoding unit;

[0039] 206A: control information decoding unit;

[0040] 206B: Arithmetic decoding unit;

[0041] 206C: context value updating unit;

[0042] 206D: context buffer;

[0043] 206E: context selection unit;

[0044] 206F: Multi-numbering unit;

[0045] 206F2: coefficient level value decoding unit;

[0046] 206G: inter-frame prediction unit;

[0047] 206H: frame buffer;

[0048] 206I: adder;

[0049] 206J: Anti-quantification Department;

[0050] 206K: Inverse wavelet transform unit;

[0051] 207: Image decoding unit. DETAILED DESCRIPTION

[0052] Below, while referring to the attached Figure 1 The embodiments of the present invention are described below. In addition, the structural elements in the following embodiments can be appropriately replaced with existing structural elements, etc., and various changes including combinations with other existing structural elements can be made. Therefore, the content of the invention described in the claims is not limited based on the description of the following embodiments.

[0053] <First Embodiment>

[0054] Below, refer to Figure 1 to Figure 1 6. The grid processing system involved in this embodiment is described.

[0055] Figure 1 1 is a diagram showing an example of the structure of the grid processing system 1 according to the present embodiment. Figure 1 As shown, the grid processing system 1 has a grid encoding device 100 and a grid decoding device 200 .

[0056] Figure 2 This is a diagram showing an example of functional blocks of the trellis decoding device 200 according to the present embodiment.

[0057] like Figure 2 As shown, the trellis decoding device 200 includes a demultiplexing unit 201 , a basic trellis decoding unit 202 , a sub-division unit 203 , a trellis decoding unit 204 , a patch integration unit 205 , a displacement decoding unit 206 and a video decoding unit 207 .

[0058] The demultiplexing unit 201 is configured to separate the multiplexed bit stream into a base grid bit stream, a displacement bit stream, and a texture bit stream.

[0059] The base grid decoding unit 202 is configured to decode the base grid bit stream, generate and output a base grid.

[0060] The sub-division unit 203 is configured to generate and output the added sub-division vertices and connection information thereof based on the basic mesh decoded by the basic mesh decoding unit 202 according to the sub-division method indicated by the control information.

[0061] Here, the base mesh, the added sub-division vertices, and the connection information thereof are collectively referred to as a “sub-division mesh”.

[0062] The mesh decoding unit 204 is configured to generate and output a decoded mesh using the sub-division mesh generated by the sub-division unit 203 and the displacement amount decoded by the displacement amount decoding unit 206 .

[0063] The patch integration unit 205 is configured to integrate and output a plurality of patches of the decoded meshes generated by the mesh decoding unit 206 .

[0064] The displacement amount decoding unit 206 is configured to decode the displacement amount bit stream and generate and output the displacement amount.

[0065] The video decoding unit 207 is configured to decode and output textures by video coding. For example, the video decoding unit 207 can use HEVC of Non-Patent Document 1.

[0066] (Displacement Decoding Unit 206)

[0067] like Figure 3 As shown, the displacement decoding unit 206 has a control information decoding unit 206A, an arithmetic decoding unit 206B, a context value updating unit 206C, a context buffer...206D, a context selection unit 206E, a multi-numbering unit 206F, a coefficient level value decoding unit F2, an inter-frame prediction unit 206G, a frame buffer 206H, an adder 206I, an inverse quantization unit 206J and an inverse wavelet transform unit 206K.

[0068] The control information decoding unit 206A is configured to output control information by performing variable length decoding on the received displacement bit stream.

[0069] The arithmetic decoding unit 206B is configured to perform arithmetic decoding on the received displacement bit stream and output a binarized syntax. The details will be described later.

[0070] The context value update unit 206C is configured to update the context value using the binarization syntax and output the updated context value to the frame buffer 206D. The details will be described later.

[0071] The context selection unit 206E is configured to generate and output a context value (output context value) using the context value read from the context buffer 206D, the bit position, and the syntax. The details will be described later.

[0072] The context buffer 206D is configured to acquire and accumulate context values, bit positions, and syntax, and is configured to output these based on control information (not shown).

[0073] The multi-bit conversion unit 206F is configured to generate and output syntax by multi-bit conversion and binarization. The generated (calculated) syntax is also output to the context buffer 206D as bit positions and syntax.

[0074] The coefficient level value decoding unit 206F2 is configured to generate and output coefficient level values ​​according to syntax.

[0075] The inter-frame prediction unit 206G is configured to generate and output a predicted displacement using the reference frame read from the frame buffer 206D.

[0076] The frame buffer H is configured to acquire and accumulate the decoded displacement. The frame buffer H is configured to output the decoded displacement of the corresponding vertex in the reference frame in response to control information (not shown).

[0077] The adder 206I is configured to obtain the prediction residual and the prediction displacement. The adder 206I is configured to add these and generate and output the decoded displacement. The generated (calculated) decoded displacement is also output to the frame buffer 206H.

[0078] The inverse quantization unit 206J is configured to generate and output transform coefficients by inverse quantizing the coefficient level values.

[0079] The inverse wavelet transform unit 206K is configured to generate and output a prediction residual by performing an inverse wavelet transform on the transform coefficients. The inverse wavelet transform is the inverse transform of the inverse wavelet transform. The inverse wavelet transform is a method that uses a wavelet function as a basis, amplifies the low-frequency components, and reduces the high-frequency components, thereby being able to analyze spatial and frequency information at the same time.

[0080] (Syntactic structure)

[0081] Below, refer to Figures 4 to 8 Explain the syntactic structure.

[0082] First, when encoding, the coefficient level value of the displacement amount is represented by a matrix of size 3×N in each frame. 3 represents the dimension in the spatial region, and N represents the total number of sub-division vertices. The matrix is ​​divided into blocks and encoded in units of blocks.

[0083] The block size can be of 3×n size (n < N), or can be of 1×n size. Alternatively, as the block size, 1×n size and 2×n size can be used in combination. For matrix elements that do not meet the block size, the block is composed of the largest d×m size (d = 1, 2, 3, m < n).

[0084] n can be changed for each block. For example, n can be determined by the sub - division level represented by control information and the total number of coefficient level values at each level (n1, n2, …). Here, the sub - division level represents the number of sub - divisions. For example, when the sub - division level is 4, it can be composed of 4 blocks of 3×n1, 3×n2, 3×n3, 3×n4.

[0085] Figure 4 It is a diagram showing an example of a syntactic structure. Syntax can be defined in units of matrices and in units of blocks.

[0086] First, the syntax defined in units of matrices is described.

[0087] lastt_sig_coeff_prefix represents the prefix of the coordinate position of the first non - zero coefficient in the scanning order. lastt_sig_coeff_suffix represents the suffix of the coordinate position of the first non - zero coefficient in the scanning order.

[0088] For example, the prefix is expressed by slicing and binary - conversion, and the suffix is expressed by a fixed length. Figure 5 It is a diagram showing the prefix code string and the suffix code string when the maximum value is 32.

[0089] Second, the syntax defined in units of blocks is described.

[0090] coded_block_flag is a flag indicating that there are non - zero coefficients within the block. Only 1 such flag is defined for each block.

[0091] last_sig_coeff_block_prefix represents the prefix of the coordinate position of the first non - zero coefficient in the scanning order within the block. last_sig_coeff_block_suffix represents the suffix of the coordinate position of the first non - zero coefficient in the scanning order within the block. sig_coeff_flag is a flag indicating whether it is a non - zero coefficient.

[0092] coeff_abs_level_greater1_flag is a flag indicating whether the absolute value of the coefficient (non - zero coefficient) is 2 or more. An upper limit such as 8 can be set for the total number of coefficients represented by this flag.

[0093] coeff_abs_level_greater2_flag is a flag indicating whether the absolute value of the leading coefficient having an absolute value of 2 or more (non-zero coefficient) in the scan order is greater than or equal to 3. coeff_sign_flag is a flag indicating the sign code of the coefficient.

[0094] coeff_abs_level_remaining indicates a value obtained by subtracting a value expressed by the above-mentioned notation from the absolute value of the coefficient. coeff_abs_level_remaining is expressed by, for example, a k-th order Exponential Golomb code. Figure 6 is a diagram showing the prefix code string and the suffix code string of the k-th order Exponential Golomb code.

[0095] Figure 7 and Figure 8 is a diagram showing a specific example of a syntactic structure. Figure 7 As shown, the coefficient level values ​​are decoded according to each syntax, and then, as Figure 8 As shown, the decoded coefficient level values ​​are rearranged.

[0096] (Arithmetic Decoding Unit 206B)

[0097] The arithmetic decoding unit 206B targets binary. The arithmetic decoding unit 206B defines a number axis from 0 to 1, divides and uses the interval. The interval is divided by the occurrence probability of binary (hereinafter referred to as context value).

[0098] A binary decimal is input to the arithmetic decoding unit 206B, and the arithmetic decoding unit 206B decodes the original value according to which interval on the number axis the binary decimal is included.

[0099] Here, the context value may be always fixed or may be changed for each bit of the input signal. When the context value is changed for each bit, the arithmetic decoding unit 206B receives the context value from the context selection unit 206E.

[0100] (Context Value Updater 206C)

[0101] The context value updating unit 206C updates the context value every time 1 bit is decoded.

[0102] Here, the context value updating unit 206C sets the symbol with a higher occurrence probability between 0 and 1 as the MPS (Most Probable Symbol) and sets the symbol with a lower occurrence probability as the LPS (Least Probable Symbol).

[0103] The context value updating unit 206C may use the probability update table to slightly update the probability value when MPS occurs, and to significantly update the probability value when LPS occurs.

[0104] (Context selection unit 206E)

[0105] The following syntax is decoded by the arithmetic decoding unit 206B and selected by the context selection unit 206E. In addition, since the selection method is different for each syntax, an example of the selection method is described below.

[0106] last_sig_coeff_prefix: context selection unit 206E Fig. 9 As shown, a context number table can be made based on the matrix size or the bit position.

[0107] last_sig_coeff_block_prefix: context selection unit 206E Fig. 9 As shown, a context number table can be created based on the block size or bit position.

[0108] coded_block_flag: The context selection unit 206E is as follows Fig.10 In the decoded right adjacent block as shown, if coded_block_flag=0, the context number is set to 0, and if coded_block_flag=1, the context number is set to 1.

[0109] sig_coeff_flag: The context selection unit 206E uses the value obtained by correcting a certain reference value based on the position of the coefficient or the coded_block_flag of the decoded right adjacent block as the context number. For example, the context selection unit 206E sets the reference value to 0 in the leftmost block and to 3 in other blocks. The context selection unit 206E can correct the context number when coded_block_flag = 0 in the decoded right adjacent block. Figure 11-1 and Figure 11-3 As shown in the table, when coded_block_flag = 1, use Figure 11-2 A table like that shown.

[0110] coeff_abs_level_greater1_flag, coeff_abs_level_greater2_flag: The context selection unit 206E may set the context number to 0 when the decoded right adjacent block has a coefficient whose absolute value (level value) is greater than or equal to 2, and may set the context number to 1 in other cases.

[0111] (Operation of the coefficient level value decoding unit 206F2)

[0112] Below, refer to Fig.12 , which illustrates an example of the operation of the coefficient level value decoding unit 206F2.

[0113] like Fig.12 As shown, in step S101, the coefficient level value decoding unit 206F2 decodes all coefficients after the positions indicated by last_sig_coeff_prefix and last_sig_coeff_suffix to 0. The subsequent processing is performed in units of blocks.

[0114] In step S102, the coefficient level value decoding unit 206F2 decodes coded_block_flag.

[0115] In step S103, the coefficient level value decoding unit 206F2 determines whether coded_block_flag is 0 or 1.

[0116] When coded_block_flag=0, the coefficient level value decoding unit 206F2 decodes all coefficients in the currently processed block as 0, and the action proceeds to step S116. When coded_block_flag=1, the action proceeds to step S104.

[0117] In step S104, the coefficient level value decoding unit 206F2 decodes all coefficients after the positions indicated by last_sig_coeff_block_prefix and last_sig_coeff_block_suffix as 0 within the currently processed block.

[0118] In step S105, the coefficient level value decoding unit 206F2 decodes sig_coeff_flag.

[0119] In step S106, the coefficient level value decoding unit 206F2 determines whether sig_coeff_flag is 0 or 1.

[0120] When sig_coeff_flag=0, the operation proceeds to step S116, and when sig_coeff_flag=1, the operation proceeds to step S107.

[0121] In step S107, the coefficient level value decoding unit 206F2 decodes coeff_abs_level_greater1_flag.

[0122] In step S108, the coefficient level value decoding unit 206F2 determines whether coeff_abs_level_greater1_flag is 0 or 1.

[0123] When coeff_abs_level_greater1_flag=0, the operation proceeds to step S113 , and when coeff_abs_level_greater1_flag=1, the operation proceeds to step S109 .

[0124] In step S109, the coefficient level value decoding unit 206F2 decodes coeff_abs_level_greater2_flag.

[0125] In step S110 , the coefficient level value decoding unit 206F2 determines whether coeff_abs_level_greater2_flag is 0 or 1.

[0126] When coeff_abs_level_greater2_flag=0, the operation proceeds to step S113, and when coeff_abs_level_greater1_flag=1, the operation proceeds to step S112.

[0127] In step S112, the coefficient level value decoding unit 206F2 decodes coeff_abs_level_remaining. Here, the coefficient level value decoding unit 206F2 decodes coeff_abs_level_remaining and adds 3 to it after performing exponential Golomb decoding as the decoded coefficient level value.

[0128] In step S113, the coefficient level value decoding unit 206F2 decodes coeff_sign_flag.

[0129] In step S114, the coefficient level value decoding unit 206F2 determines whether coeff_sign_flag is 0 or 1.

[0130] When coeff_sign_flag=0, the operation proceeds to step S116, and when coeff_sign_flag=1, the operation proceeds to step S115.

[0131] In step S115, the coefficient level value decoding unit 206F2 converts the decoded coefficient into a negative value.

[0132] In step S116, the coefficient level value decoding unit 206F2 determines whether the block currently being processed is the final block.

[0133] If yes, the action ends, and if no, the action proceeds to step S111.

[0134] In step S111, the coefficient level value decoding unit 206F2 enters the processing of the next block, and the action returns to step S102.

[0135] Next, refer to Fig.13 , illustrating an example of the operations of the arithmetic decoding unit 206B, the context selection unit 206E, the context value updating unit 206C and the multi-numbering unit 206F.

[0136] like Fig.13 As shown, the arithmetic decoding unit 206B initializes the arithmetic decoding unit 206B in step S201, and sets the initial context value in step S202.

[0137] The arithmetic decoding unit 206B selects a context in step S203 , and performs arithmetic decoding in step S204 .

[0138] In step S205 , the context value updating unit 206C and the context selecting unit 206E update the context value, and in step S206 , the multi-numbering unit 206F performs multi-numbering.

[0139] The multiplexing unit 206F determines whether all decoding is completed in step S207. If so, the operation proceeds to step S208, and if not, the operation proceeds to step S203.

[0140] In step S208, the multi-numbering unit 206F saves the context value.

[0141] (Bitstream Structure)

[0142] Below, refer to Fig.14 An example of the structure of the bit stream of the displacement amount will be described.

[0143] First, the bitstream may contain a DPS (Displacement Parameter Set) as a control information set related to the decoding of the displacement amount.

[0144] Second, the bitstream may contain a frame header corresponding to the frame as a set of control information.

[0145] Third, the bitstream may contain the encoded displacements that make up the frame after the frame header.

[0146] As described above, the bit stream is configured such that the frame header and the DPS correspond to the displacement of each code.

[0147] also, Fig.14The structure shown is only an example. As long as the frame header and DPS correspond to the displacement of each code, other elements than the above can be added as structural elements of the bit stream. Fig.14 As shown, the bitstream may contain an SPS (sequence parameter set).

[0148] According to the grid decoding device 200 involved in this embodiment, by dividing the coefficient level value group of the displacement amount in the frequency region, a syntax representing coefficients with small absolute values ​​is introduced, and different context models are constructed in each frequency region, thereby improving the coding efficiency.

[0149] The above-mentioned trellis encoding device 100 and trellis decoding device 200 can be implemented as a program that causes a computer to execute each function (each process).

[0150] Industrial Applicability

[0151] In addition, according to this embodiment, for example, since comprehensive service quality can be improved in moving image communications, it can contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, "Improve the infrastructure of the information environment, promote sustainable industrialization and achieve expansion of innovation."

Claims

1. A grid decoding device, characterized in that: The grid decoding device has: A displacement decoding unit is configured to decode the displacement bit stream to generate and output the displacement, The displacement decoding unit comprises: an arithmetic decoding unit configured to generate a binarized syntax by performing arithmetic decoding on the displacement bit stream; a context value updating unit configured to update the context value using the binarization syntax; a context buffer configured to acquire and accumulate the context value, bit position and syntax; a context selection unit configured to generate an output context value using the context value read from the context buffer, the bit position, and the syntax; a multi-byte conversion unit configured to generate the syntax by multi-byte conversion of the binarized syntax and output the syntax to the context buffer; a coefficient level value decoding unit configured to generate coefficient level values ​​according to the syntax; an inverse quantization unit configured to generate a transform coefficient by inverse quantizing the coefficient level value; as well as The inverse wavelet transform unit is configured to generate a prediction residual by performing an inverse wavelet transform on the transform coefficients.

2. The grid decoding device according to claim 1, characterized in that: The arithmetic decoding unit is configured to decode the binarized syntax in units of blocks. The multi-numbering unit is configured to generate the syntax in units of blocks. The coefficient level value decoding unit is configured to generate the coefficient level value in units of blocks.

3. The grid decoding device according to claim 2, characterized in that: The coefficient level value decoding unit is constructed to generate the coefficient level value using a mark indicating that there is a non-zero coefficient in the block, the coordinate position of the non-zero coefficient at the beginning of the scanning order in the block, a mark indicating whether the coefficient of the decoding target is the non-zero coefficient, a mark indicating whether the absolute value of the non-zero coefficient is greater than 2, a mark indicating whether the absolute value of the non-zero coefficient is greater than 3, a mark indicating the positive and negative codes of the non-zero coefficient, and a value obtained by subtracting 3 from the absolute value of the non-zero coefficient.

4. The grid decoding device according to claim 3, characterized in that: The context selection unit is configured as follows: According to a flag indicating that there are non-zero coefficients in the decoded right adjacent block, a context number of the decoding target block is selected, According to a flag indicating that there is a non-zero coefficient in the decoded right adjacent block, a context number of a flag indicating a positive or negative code of the non-zero coefficient in the decoding target block is selected, When the decoded right adjacent block has a coefficient whose absolute value is greater than or equal to 2, a context number of the absolute value of the non-zero coefficient in the decoding target block is selected.

5. A grid decoding method, characterized in that: The grid decoding method has: The process of decoding the displacement bit stream to generate and output the displacement, The process comprises: A step of generating a binarized syntax by performing arithmetic decoding on the displacement bit stream; A process of updating a context value using the binarization syntax; The process of obtaining the context value, bit position and syntax and accumulating them in a context buffer; A step of generating an output context value using the context value read from the context buffer, the bit position and the syntax; A step of generating the syntax by multi-binarizing the binarized syntax and outputting the syntax to the context buffer; A step of generating coefficient level values ​​according to the syntax; The step of generating transform coefficients by inverse quantizing the coefficient level values; and A step of generating a prediction residual by performing an inverse wavelet transform on the transform coefficients.

6. A program product comprising a program for causing a computer to function as a trellis decoding device, wherein: The trellis decoding device comprises: a displacement decoding unit configured to decode a displacement bit stream to generate and output a displacement; The displacement decoding unit comprises: an arithmetic decoding unit configured to generate a binarized syntax by performing arithmetic decoding on the displacement bit stream; a context value updating unit configured to update the context value using the binarization syntax; a context buffer configured to acquire and accumulate the context value, bit position and syntax; a context selection unit configured to generate an output context value using the context value read from the context buffer, the bit position, and the syntax; a multi-byte conversion unit configured to generate the syntax by multi-byte conversion of the binarized syntax and output the syntax to the context buffer; a coefficient level value decoding unit configured to generate coefficient level values ​​according to the syntax; an inverse quantization unit configured to generate a transform coefficient by inverse quantizing the coefficient level value; as well as The inverse wavelet transform unit is configured to generate a prediction residual by performing an inverse wavelet transform on the transform coefficients.

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