JP6956543B2 - Determination device, coding device, decoding device and program - Google Patents

Description

The present invention relates to a determination device, a coding device, a decoding device and a program.

Research is being conducted on a coding method for compressing the amount of data when transmitting or storing still images and moving images. In recent years, in video (moving image) coding technology, ultra-high resolution video represented by 8K-SHV (Super High Vision) has become widespread, and moving images with a huge amount of data can be transmitted to broadcast waves and IP networks. As a method for transmitting with, there are known coding methods such as AVC (Advanced Video Coding) / H.264 and HEVC (High Efficiency Video Coding) / H.265.

In the above-mentioned coding method, hierarchical quadtree division is adopted for block division, and the optimum block division shape is selected and selected on the encoding device (encoder) side according to the texture contained in the original image. Information related to the block division shape is transmitted to the decoding device (decoder) side (see, for example, Non-Patent Document 1).

In the next-generation video coding method performance evaluation software (JEM) jointly studied by MPEG (Moving Picture Experts Group) and ITU (International Telecommunication Union), in addition to hierarchical quadtree division as an extension of HEVC, A hierarchical binary tree division (QTBT: Quad Tree plus Binary Tree) has been introduced, making it possible to select a more flexible block division shape (see FIG. 6).

As shown in FIG. 7, there are 67 intra-prediction modes in JEM, Planar mode (mode 0), DC mode (mode 1), and directional prediction mode (modes 2-66). One of the optimum intra prediction modes is selected from the 67 intra prediction modes, and the selected intra prediction mode is transmitted to the decoding device side.

When performing intra-prediction, a decoded pixel adjacent to the coded target block is used as a reference pixel.

However, depending on the coded block, the adjacent blocks on the lower left and upper right may not have been decoded. In such a case, as shown in FIG. 8A, the decoded pixels closest to the undecoded pixels among the reference pixels are sequentially extrapolated to the 0th order to create the reference pixels. As described above, as shown in FIG. 8B, it is presumed that the intra-prediction using the undecoded reference pixel has lower prediction accuracy than the intra-prediction using the decoded reference pixel.

Further, as shown in FIG. 9, the decrease in the prediction accuracy in the intra prediction using the reference pixels that have not been decoded becomes more remarkable in the block subjected to the binary tree division.

Therefore, if the adjacent blocks in the lower left and upper right are not decoded, it is considered that the probability that the intra prediction mode using the reference pixels in the adjacent blocks will be used is low. Nevertheless, if the code amount is evenly distributed to all the intra prediction modes, there is a problem that the coding efficiency is reduced.

Next, a method of allocating the code amount to the existing intra-prediction mode for solving such a problem will be described.

(MPM)
First, as a method of allocating the code amount to the intra prediction mode, a mechanism of allocating a small amount of code to the intra prediction mode used in a specific peripheral block of each block considered to be used is used. ing. Such an intra prediction mode is called MPM (Most Problem Mode).

In JEM, 6 intra prediction modes can be selected as the MPM. The code amount assigned to the six intra prediction modes is set to be smaller than the code amount assigned to the other 61 (67-6) intra prediction modes.

(Selected Mode)
Second, for the intra prediction mode not selected as the MPM, first, Selected Mode (16 intra prediction modes) is specified. The Selected Mode is evenly selected from 61 intra-prediction modes to one intra-prediction mode for every four intra-prediction modes, and a fixed-length 4-bit is assigned to each intra-prediction mode.

(Non-Selected Mode)
Third, for the remaining 45 (67-6-16) intra-prediction modes, a fixed-length 5 bits or a fixed-length 6-bit is assigned as the Non-Selected Mode by the Truncated Binary Coding. At this time, 5 bits are assigned in ascending order from the smallest mode number of the intra prediction mode, and 6 bits are assigned in the intra prediction mode having the larger mode number (see FIG. 7).

As an example of the method of assigning the code amount to each intra prediction mode (Selected Mode and Non-Selected Mode) other than MPM, the MPM is an intra prediction mode in which the mode number is {0, 1, 2, 18, 34, 50}. Consider the case where.

First, from 61 intra prediction modes other than MPM, the mode numbers are {3, 7, 11, 15, 20, 24, 28, 32, 37, 41, 45, 49, 54, 58, 62, 66. } Is selected as the Selected Mode. In addition to the MPM identification flag and the Selected Mode identification flag, a fixed-length 4-bit code is assigned to each of the intra prediction modes.

For intra prediction modes other than MPM and Selected Mode, a code is assigned as Non-Selected Mode. Like the Selected Mode, the Non-Selected Mode is assigned an MPM identification flag and a Selected Mode identification flag. In addition, in ascending order of mode number, up to 19 intra prediction modes have a fixed-length 5-bit code. Is assigned, and a fixed-length 6-bit code is assigned to the other 26 intra prediction modes.

An example of Non-Selected Mode when MPM and Selected Mode are selected as described above is shown below.
--Non-Selected Mode (5 bits): {4, 5, 6, 8, 9, 10, 12, 13, 14, 16, 17, 19, 21, 22, 23, 25, 26, 27, 29}
--Non-Selected Mode (6 bits): {Other intra prediction modes}

Supervised by Ei Okubo, "Impress Standard Textbook Series H.265 / HEVC Textbook", Impress Japan Co., Ltd., October 21, 2013

However, in the above technique, it is stipulated that the selected mode is evenly selected from the entire range of the intra prediction mode each time, and a small code amount is assigned to the fixed intra prediction mode of the non-selected mode each time. However, there is a problem that it leads to a reduction in coding efficiency.

Therefore, the present invention has been made to solve the above-mentioned problems, and is a determination device, a coding device, a decoding device, and a program capable of reducing the code amount in the intra prediction and improving the coding efficiency. The purpose is to provide.

The first feature of the present invention is a determination device configured to divide the original image of each frame constituting the moving image into blocks and determine the intra prediction mode of each block, and the division of the blocks. The code amount allocation determination unit is configured so that the code amount allocation method for the intra prediction mode other than the priority prediction mode can be changed based on the shape, and the priority prediction mode is the block. The gist is that it is the intra-prediction mode used in a specific peripheral block of.

A second feature of the present invention is a coding device configured to divide an original image in frame units constituting a moving image into blocks and encode the original image, which is described in the first feature described above. The gist is to have a determination device.

A third feature of the present invention is a decoding device configured to divide an original image in frame units constituting a moving image into blocks and decode the original image, and the determination device according to the first feature described above. The gist is to have.

A fourth feature of the present invention is a program for causing a computer to function as the coding device described in the second feature described above.

A fifth feature of the present invention is a program for making a computer function as a decoding device according to the third feature described above.

According to the present invention, it is possible to provide a coding device, a decoding device and a program capable of reducing the code amount in the intra prediction and improving the coding efficiency.

FIG. 1 is a diagram showing an example of a functional block of the coding device 1 according to the first embodiment. FIG. 2 is a diagram for explaining an example of a method of changing the code amount allocation in the Selected Mode by the determination device 1 according to the first embodiment. FIG. 3 is a diagram for explaining an example of a method of changing the code amount allocation in the Non-Selected Mode by the determination device 1 according to the first embodiment. FIG. 4 is a diagram showing an example of the divided shape of the block when changing the code amount allocation in the Selected Mode and the Non-Selected Mode by the determination device 1 according to the first embodiment. FIG. 5 is a diagram showing an example of a functional block of the decoding device 3 according to the first embodiment. FIG. 6 is a diagram for explaining the prior art. FIG. 7 is a diagram for explaining the prior art. FIG. 8 is a diagram for explaining the prior art. FIG. 9 is a diagram for explaining the prior art.

(First Embodiment)
Hereinafter, the coding device 1 and the decoding device 3 including the determination device A according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 5. Here, the determination device A is configured to divide the original image of each frame constituting the moving image into blocks and determine the intra prediction mode of each block.

The coding device 1 and the decoding device 3 according to the present embodiment are configured to correspond to the above-mentioned intra prediction mode (see FIG. 7) in JEM. Further, the coding device 1 and the decoding device 3 according to the present embodiment are configured to correspond to QTBT.

The coding device 1 and the decoding device 3 according to the present embodiment are configured to be compatible with any moving image coding method as long as it is a moving image coding method that performs intra-prediction.

The coding device 1 according to the present embodiment is configured to divide the original image of each frame constituting the moving image into blocks and encode the original image. Hereinafter, such a block may be a CU (Coding Unit), a PU (Prediction Unit), or a TU (Transform Unit).

As shown in FIG. 1, the coding apparatus 1 according to the present embodiment includes a block dividing unit 11, a residual signal generation unit 12, a conversion unit 13, a quantization unit 14, an entropy coding unit 15, and the entropy coding unit 15. It includes an inverse quantization unit 16, an inverse conversion unit 17, a decoded image generation unit 18, a memory 19, a code amount allocation determination unit 20, and an intra prediction unit 21.

The block division unit 11 is configured to perform quadtree division or binary tree division for each block, and output a flag indicating the division shape of the block to the residual signal generation unit 12 or the like.

The residual signal generation unit 12 generates a residual signal (predicted difference image) indicating the difference between the original image of each block divided by the block dividing unit 11 and the predicted image generated by the intra prediction unit 21. It is configured.

The orthogonal transform unit 13 is configured to perform orthogonal transform processing on the residual signal generated by the residual signal generation unit 12 to obtain an orthogonal transform coefficient.

The quantization unit 14 is configured to perform a quantization process on the orthogonal transformation coefficient generated by the orthogonal transform unit 13 to obtain a quantized orthogonal transformation coefficient.

The entropy coding unit 15 is configured to perform entropy coding processing on the quantized orthogonal transformation coefficient and the intra prediction mode of each block.

The inverse quantization unit 16 is configured to perform an inverse quantization process on the quantized conversion coefficient generated by the quantization unit 14 to generate an orthogonal conversion coefficient.

The inverse orthogonal transform unit 17 is configured to perform an inverse orthogonal transform process on the orthogonal transform coefficient generated by the inverse quantization unit 16 to generate a residual signal.

The decoded image generation unit 18 is configured to generate a decoded image by adding the predicted image generated by the intra prediction unit 21 to the residual signal generated by the inverse orthogonal transform unit 17.

The memory 19 is configured to hold the decoded image generated by the decoded image generation unit 18 so as to be available as a reference image.

The code amount allocation determination unit 20 can change the code amount allocation method for the intra prediction mode other than the MPM (priority prediction mode) based on the division shape of each block divided by the block division unit 11. It is configured.

Here, the code amount allocation determination unit 20 can change the code amount allocation method for the intra prediction mode other than MPM based on whether or not the reference pixel in the adjacent block of each block has been decoded. It may be configured in.

Hereinafter, in the present embodiment, the number of all intra prediction modes is 67, 6 intra prediction modes can be selected as MPM, and 16 intra prediction modes are selected as Selected Mode (selection prediction mode). A case where it is possible and 45 intra-prediction modes can be selected as a Non-Selected Mode (non-selective prediction mode) will be described as an example.

In the existing mechanism, the Selected Mode has a predetermined interval (4 intra prediction modes) in ascending order from the smallest mode number in the entire range of the intra prediction modes not selected as the MPM, as shown in FIG. 2 (a). It is stipulated that they are evenly selected at intervals of one intra-prediction mode.

Here, the code amount allocation determination unit 20 is configured to change the code amount allocation method for the intra prediction mode other than MPM by changing at least one of the above-mentioned predetermined interval and the range that can be selected as the Selected Mode. It may have been.

For example, as shown in FIG. 2B, the code amount allocation determination unit 20 has mode number 2 (small mode) in the range of the intra prediction modes of mode numbers 2 to 50 among the intra prediction modes not selected as MPM. Selected Modes may be selected evenly at intervals of one intra-prediction mode for every three intra-prediction modes in ascending order from (number).

Alternatively, as shown in FIG. 2C, the code amount allocation determination unit 20 has a mode number 10 (small mode) in the range of the intra prediction modes of mode numbers 10 to 58 among the intra prediction modes not selected as MPM. Selected Modes may be selected evenly at intervals of one intra-prediction mode for every three intra-prediction modes in ascending order from (number).

Alternatively, as shown in FIG. 2D, the code amount allocation determination unit 20 has a mode number 66 (large mode) in the range of the intra prediction modes of mode numbers 18 to 66 among the intra prediction modes not selected as MPM. Selected Modes may be selected evenly at intervals of one intra-prediction mode for every three intra-prediction modes in descending order from the number).

Further, in the existing mechanism, as shown in FIG. 3A, for the Non-Selected Mode, the mode number 2 (small mode number) is used in the entire range of the intra prediction modes not selected as the MPM and the Selected Mode. Select in ascending order, assign a code amount of 5 bits (first predetermined length) to a predetermined number (for example, 19) of intra prediction modes, and 6 bits (second predetermined length) for the remaining intra prediction modes. It is specified to allocate the code amount of (long).

Here, as shown in FIG. 3B, the code amount allocation determination unit 20 has a mode number 66 (larger) for the Non-Selected Mode in the entire range of the intra prediction mode not selected as the MPM and the Selected Mode. By selecting from the mode number) in descending order, the method of assigning the code amount to the intra prediction mode other than MPM may be changed.

For example, in the code amount allocation determination unit 20, as shown in FIG. 4A, the division shape of the target block # 3 is vertically long, and the reference pixel in the block # 2 adjacent to the lower left of the block # 3 is decoded. If the reference pixel in the block adjacent to the upper right of the block # 3 has not been decoded, as shown in FIG. 2 (b), among the intra prediction modes not selected as the MPM, the mode numbers 2 to 50 In the range of the intra prediction mode, even if the Selected Mode is selected evenly at intervals of one intra prediction mode for each of the three intra prediction modes in ascending order from the mode number 2 (small mode number). good.

In such a case, as shown in FIG. 3A, the code amount allocation determination unit 20 selects from mode number 2 (smaller mode number) in ascending order in the entire range of the intra prediction mode not selected as MPM and Selected Mode. Then, a predetermined number (for example, 19) of intra-prediction modes may be allocated a 5-bit code amount, and the remaining intra-prediction modes may be allocated a 6-bit code amount. ..

In the example of FIG. 4A, first, the block # 1 and the block # 2 / # 3 / # 4 are divided into binary trees, and secondly, the block # 2 and the block # 3 / # 4 are divided into two. It is divided into trees, and thirdly, it is divided into blocks # 3 and blocks # 4. In such an example, it is assumed that the coding process (decoding process) is performed in the order of block # 1 → block # 2 → block # 3 → block # 4.

Further, as shown in FIG. 4B, the code amount allocation determination unit 20 has a vertically long divided shape of the target block # 3, and the reference pixel in the block # 5 adjacent to the lower left of the block # 3 is decoded. If the reference pixel in the block adjacent to the upper right of the block # 3 is not already decoded, as shown in FIG. 2 (c), the mode numbers 10 to 58 of the intra prediction modes not selected as the MPM In the range of the intra prediction mode, even if the Selected Mode is selected evenly at intervals of one intra prediction mode for each of the three intra prediction modes in ascending order from the mode number 10 (small mode number). good.

In such a case, as shown in FIG. 3A, the code amount allocation determination unit 20 selects from mode number 2 (smaller mode number) in ascending order in the entire range of the intra prediction mode not selected as MPM and Selected Mode. Then, a predetermined number (for example, 19) of intra-prediction modes may be allocated a 5-bit code amount, and the remaining intra-prediction modes may be allocated a 6-bit code amount. ..

In the example of FIG. 4B, firstly, the block # 1, block # 2 / # 3, block # 4 and block # 5 are divided into quadtrees, and secondly, block # 2 and block # 3 are divided. It is divided into two trees. In such an example, it is assumed that the coding process (decoding process) is performed in the order of block # 1 → block # 2 → block # 3 → block # 4 → block # 5.

Further, as shown in FIG. 4C, the code amount allocation determination unit 20 has a square division shape of the target block # 4, and the reference pixel in the block adjacent to the lower left of the block # 4 has been decoded. If the reference pixel in the block adjacent to the upper right of the block # 4 is not decoded, as shown in FIG. 2C, the intra-prediction of mode numbers 10 to 58 among the intra-prediction modes not selected as MPM is performed. In the range of modes, Selected Modes may be selected evenly at intervals of one intra-prediction mode for every three intra-prediction modes in ascending order from mode number 10 (small mode number).

In such a case, as shown in FIG. 3A, the code amount allocation determination unit 20 selects from mode number 2 (smaller mode number) in ascending order in the entire range of the intra prediction mode not selected as MPM and Selected Mode. Then, a predetermined number (for example, 19) of intra-prediction modes may be allocated a 5-bit code amount, and the remaining intra-prediction modes may be allocated a 6-bit code amount. ..

In the example of FIG. 4C, the block # 1, the block # 2, the block # 3, and the block # 4 are divided into quadtrees. In such an example, it is assumed that the coding process (decoding process) is performed in the order of block # 1 → block # 2 → block # 3 → block # 4.

Further, as shown in FIG. 4D, the code amount allocation determination unit 20 has a horizontally long divided shape of the target block # 4, and the reference pixel in the block adjacent to the lower left of the block # 4 has been decoded. If the reference pixel in the block adjacent to the upper right of the block # 4 is not decoded, as shown in FIG. 2C, the intra prediction of mode numbers 10 to 58 among the intra prediction modes not selected as MPM is shown. In the range of modes, Selected Modes may be selected evenly at intervals of one intra-prediction mode for every three intra-prediction modes in ascending order from mode number 10 (smaller mode number).

In such a case, as shown in FIG. 3B, the code amount allocation determination unit 20 selects from mode number 66 (larger mode number) in descending order in the entire range of the intra prediction mode not selected as MPM and Selected Mode. Then, a predetermined number (for example, 19) of intra-prediction modes may be allocated a 5-bit code amount, and the remaining intra-prediction modes may be allocated a 6-bit code amount. ..

In the example of FIG. 4D, firstly, the block # 1, block # 2, block # 3 / # 4, and block # 5 are divided into quadtrees, and secondly, block # 3 and block # 4 It is divided into two trees. In such an example, it is assumed that the coding process (decoding process) is performed in the order of block # 1 → block # 2 → block # 3 → block # 4 → block # 5.

Further, as shown in FIG. 4E, the code amount allocation determination unit 20 has a horizontally long divided shape of the target block # 3, and the reference pixel in the block # 5 adjacent to the lower left of the block # 3 is decoded. If the reference pixel in the block adjacent to the upper right of the block # 3 has been decoded, as shown in FIG. 2 (d), the mode numbers 18 to 66 of the intra prediction modes not selected as the MPM are shown. In the range of the intra prediction mode of, the Selected Mode is selected evenly at intervals of one intra prediction mode for every three intra prediction modes in descending order from the mode number 66 (larger mode number). May be good.

In such a case, as shown in FIG. 3B, the code amount allocation determination unit 20 selects from mode number 66 (larger mode number) in descending order in the entire range of the intra prediction mode not selected as MPM and Selected Mode. Then, a predetermined number (for example, 19) of intra-prediction modes may be allocated a 5-bit code amount, and the remaining intra-prediction modes may be allocated a 6-bit code amount. ..

In the example of FIG. 4 (e), firstly, the binary tree is divided into block # 1 and block # 2 / # 3 / # 4, and secondly, it is divided into block # 2 and block # 3 / # 4. It is divided into trees, and thirdly, it is divided into blocks # 3 and blocks # 4. In such an example, it is assumed that the coding process (decoding process) is performed in the order of block # 1 → block # 2 → block # 3 → block # 4.

The intra prediction unit 21 generates a prediction image of each block based on the intra prediction mode of each block determined by the coding device 1 (determining device A) and the reference image of each block held in the memory 19. It is configured as follows.

Further, the decoding device 3 according to the present embodiment is configured to divide the original image of each frame constituting the moving image into blocks and decode it.

As shown in FIG. 5, the decoding device 3 according to the present embodiment includes an entropy decoding unit 31, an inverse quantization unit 32, an inverse conversion unit 33, an intra prediction unit 34, a decoded image generation unit 35, and a memory. 36 and a code amount allocation determination unit 37 are provided.

The entropy decoding unit 31 performs an entropy decoding process on the stream output from the coding device 1 so as to decode the quantized orthogonal transformation coefficient or the like from the stream output from the coding device 1. It is configured.

The inverse quantization unit 32 is configured to generate an orthogonal transformation coefficient by performing an inverse quantization process on the quantized orthogonal transformation coefficient output by the entropy decoding unit 31.

The inverse transformation unit 33 is configured to generate a residual signal by performing an inverse transformation process (for example, an inverse orthogonal transformation process) on the orthogonal transformation coefficient output by the inverse quantization unit 32.

The intra prediction unit 34 is configured to generate a prediction image based on the intra prediction mode of each block output by the entropy decoding unit 31 and the reference image of each block held in the memory 36.

The decoded image generation unit 35 is configured to generate a decoded image by adding the predicted image generated by the intra prediction unit 34 and the residual signal generated by the inverse conversion unit 33.

The memory 36 is configured to hold the decoded image generated by the decoded image generation unit 35 so as to be available as a reference image for intra-prediction.

The code amount allocation determination unit 37 has the same function as the code amount allocation unit 20 described above.

According to the determination device A (encoding device 1 and decoding device 3) according to the present embodiment, when a specific adjacent block of each block has not been decoded, depending on the location of the adjacent block and the divided shape of each block. By changing the code amount assigned to each intra prediction mode, the code amount in the intra prediction can be reduced and the coding efficiency can be improved.

(Other embodiments)
Although the present invention has been described by the embodiments described above, the statements and drawings that form part of the disclosure in such embodiments should not be understood as limiting the invention. Such disclosure will reveal to those skilled in the art various alternative embodiments, examples and operational techniques.

Further, although not particularly mentioned in the above-described embodiment, a program for causing a computer to execute each process performed by the above-mentioned coding device 1 and decoding device 3 may be provided. The program may also be recorded on a computer readable medium. Computer-readable media can be used to install such programs on computers. Here, the computer-readable medium on which such a program is recorded may be a non-transient recording medium. The non-transient recording medium is not particularly limited, but may be, for example, a recording medium such as a CD-ROM or a DVD-ROM.

Alternatively, even if a chip composed of a memory for storing a program for realizing at least a part of the functions in the encoding device 1 and the decoding device 3 described above and a processor for executing the program stored in the memory is provided. good.

A ... Determination device 1 ... Coding device 11 ... Block division unit 12 ... Residual signal generation unit 13 ... Conversion unit 14 ... Quantization unit 15 ... Entropy coding unit 16 ... Inverse quantization unit 17 ... Inverse conversion unit 18 ... Decoding Image generation unit 19 ... Memory 20 ... Code amount allocation determination unit 21 ... Intra prediction unit 31 ... Entropy decoding unit 32 ... Inverse quantization unit 33 ... Inverse conversion unit 34 ... Intra prediction unit 35 ... Decoded image generation unit 36 ... Memory 37 ... Code amount allocation judgment unit

Claims (8)

It is a determination device configured to divide the original image of each frame constituting the moving image into blocks and determine the intra prediction mode of each block.
Based on the divided shape of the block, the code amount is assigned to the selected prediction mode selected from the intra prediction modes other than the priority prediction mode, and neither the priority prediction mode nor the selection prediction mode is selected. It is provided with a code amount allocation determination unit configured so that the code amount allocation method for the non-selection prediction mode, which is the intra-prediction mode, and the code amount allocation mode can be changed in different modes from each other.
The priority prediction mode is a determination device, which is an intra prediction mode used in a specific peripheral block of the block. The code amount allocation determination unit can change the code amount allocation method based on the divided shape of the block and whether or not the reference pixel in the adjacent block of the block has been decoded. The determination device according to claim 1, wherein the determination device is configured in the above. It is a determination device configured to divide the original image of each frame constituting the moving image into blocks and determine the intra prediction mode of each block.
It is provided with a code amount allocation determination unit configured so that the code amount allocation method for the intra prediction mode other than the priority prediction mode can be changed based on the divided shape of the block.
The priority prediction mode is an intra prediction mode used in a specific peripheral block of the block.
Regarding the selection prediction mode among the intra prediction modes other than the priority prediction mode, the code amount allocation determination unit is in ascending order or in ascending order from the smallest mode number among the intra prediction modes not selected as the priority prediction mode. It is configured to select evenly at predetermined intervals in descending order from the number.
The code amount allocation determination unit is configured to change the code amount allocation method by changing at least one of the predetermined interval and the range that can be selected as the selection prediction mode. that decision apparatus. It is a determination device configured to divide the original image of each frame constituting the moving image into blocks and determine the intra prediction mode of each block.
It is provided with a code amount allocation determination unit configured so that the code amount allocation method for the intra prediction mode other than the priority prediction mode can be changed based on the divided shape of the block.
The priority prediction mode is an intra prediction mode used in a specific peripheral block of the block.
Regarding the selection prediction mode among the intra prediction modes other than the priority prediction mode, the code amount allocation determination unit is in ascending order or in ascending order from the smallest mode number among the intra prediction modes not selected as the priority prediction mode. It is configured to select evenly at predetermined intervals in descending order from the number.
Regarding the non-selection prediction mode among the intra prediction modes other than the priority prediction mode, the code amount allocation determination unit has a smaller mode number of the priority prediction mode and the intra prediction mode not selected as the selection prediction mode. from by altering choose from or larger mode number is selected in ascending descending order, decision device you characterized in that it is configured to change the way of assignment the code amount. A coding device configured to divide the original image of each frame constituting a moving image into blocks and encode them.
A coding device including the determination device according to any one of claims 1 to 4. It is a decoding device configured to divide the original image of each frame constituting the moving image into blocks and decode it.
A decoding device comprising the determination device according to any one of claims 1 to 4. A program for causing a computer to function as the coding device according to claim 5. A program for causing a computer to function as the decoding device according to claim 6.

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