JP2020202417A - Image decoding device and image coding device - Google Patents

Abstract

To provide an image decoding device to which inverse secondary conversion can be applied more preferably and a related technique thereof.SOLUTION: A moving image decoding device is an image decoding device that reversely converts a conversion coefficient for each conversion unit, and includes a first scaling part that scales with respect to the decoded conversion coefficient, a second conversion unit that applies inverse secondary conversion to the conversion coefficient, a second scaling unit that scales with respect to the conversion coefficient after conversion by the second conversion unit, and a first conversion unit that applies inverse core conversion to the conversion coefficient after scaling by the first scaling unit or the second scaling unit.SELECTED DRAWING: Figure 21

Description

Embodiments of the present invention relate to an image decoding device and an image coding device.

In order to efficiently transmit or record an image, an image coding device that generates coded data by encoding the image and an image decoding device that generates a decoded image by decoding the coded data It is used.

Specific image coding methods include, for example, H.264 / AVC and HEVC (High-Efficiency Video).
Coding) method and the like.

In such an image coding method, the image (picture) constituting the image is a slice obtained by dividing the image, a coding tree unit (CTU) obtained by dividing the slice, and the like. A coding unit (sometimes called a coding unit (CU)) obtained by dividing a coding tree unit, and a transformation unit (TU: Transform Unit) obtained by dividing a coding unit. ) Is managed by a hierarchical structure, and each CU is encoded / decoded.

Further, in such an image coding method, a predicted image is usually generated based on a locally decoded image obtained by encoding / decoding an input image, and the predicted image is subtracted from the input image (original image). The prediction error (sometimes referred to as a "difference image" or "residual image") thus obtained is encoded. Examples of the method for generating a prediction image include inter-screen prediction (inter-screen prediction) and in-screen prediction (intra-prediction).

Further, Non-Patent Document 1 is mentioned as a recent image coding and decoding technique. Non-Patent Document 1 discloses an image coding device that derives a conversion coefficient by converting each coefficient after conversion of a prediction error for each conversion unit by RST (Reduced Secondary Transform) conversion, that is, a secondary transformation. .. Further, Non-Patent Document 1 discloses an image decoding apparatus that reversely converts the conversion coefficient for each conversion unit by inverse secondary conversion. Non-Patent Document 2 discloses a technique of performing different scaling for each position of the conversion coefficient using a quantization matrix.

"CE6: Reduced Secondary Transform (RST) (CE6-3.1)", JVET-N0193-v5, Joint Video Experts Team (JVET) of ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC 29/WG 11, 2019-03-27 "CE7-related: Support of signaling default and user-defined scaling matrices", JVET-N0090-v3, Joint Video Experts Team (JVET) of ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC 29/WG 11 , 2019-03-23

It is required to apply these more preferably in the techniques related to secondary conversion and inverse secondary conversion as in Non-Patent Document 1.

An object of the present invention is to provide an image decoding apparatus and related techniques to which an inverse secondary conversion can be applied more preferably.

In order to solve the above problems, the moving image decoding device according to one aspect of the present invention is an image decoding device that reversely converts the conversion coefficient for each conversion unit, and is a first scaling device that scales with respect to the decoded conversion coefficient. A scaling unit, a second conversion unit that applies an inverse secondary conversion to the conversion coefficient, a second scaling unit that scales the conversion coefficient after conversion by the second conversion unit, and the first conversion unit. It is characterized by including a scaling unit or a first conversion unit that applies an inverse core conversion to the conversion coefficient after scaling by the second scaling unit.

In order to solve the above problems, in the moving image decoding apparatus according to one aspect of the present invention, the above-mentioned first scaling unit uses a shift value that uses the size of the conversion unit, or a predetermined size that does not use the size of the variable unit. A shift value of the value is derived, a scale factor using the quantization parameter is derived, the first scaling is performed on the conversion coefficient using the shift value and the scale factor, and the second scaling unit is a quantum. When the quantization matrix is effective, a scale factor using the quantization matrix is derived, and the above scale factor is used to perform a second scaling on the conversion coefficient.

In order to solve the above problems, in the moving image decoding apparatus according to one aspect of the present invention, the above-mentioned first scaling unit is a shift value using the size of the conversion unit when the secondary conversion is effective, and other than that. In this case, a shift value of a predetermined value is derived without using the size of the conversion unit, a scale factor using the quantization parameter is derived, and the first scaling with respect to the conversion coefficient is performed using the shift value and the scale factor. The second scaling unit derives a shift value of a predetermined value that does not use the size of the conversion unit when the secondary conversion is valid, and a shift value that uses the size of the conversion unit in other cases. , When the quantization matrix is valid, the scale factor using the quantization matrix is derived, and in other cases, the scale factor of a predetermined value is derived, and the above scale factor is used to obtain the second scale factor with respect to the conversion coefficient. It is characterized by scaling.

In order to solve the above problems, in the moving image decoding apparatus according to one aspect of the present invention, the above-mentioned first scaling unit derives a shift value using the size of the conversion unit, and sets a scale factor using the quantization parameter. Derived, when the secondary transformation is not valid and the quantization matrix is valid, the scale factor using the quantization matrix is derived, and the first shift value and the scale factor are used for the conversion coefficient. The second scaling unit derives a scale factor using the quantization matrix when the secondary transformation is valid and the quantization matrix is valid, and the conversion is performed using the scale factor. It is characterized in that a second scaling is performed on the coefficient.

In order to solve the above problems, in the moving image decoding apparatus according to one aspect of the present invention, the above-mentioned first scaling unit derives a shift value using the size of the conversion unit, the secondary conversion is effective, and the quantum. When the quantization matrix is valid, a scale factor of a predetermined value is derived, a scale factor using the quantization parameter is derived, and when the secondary transformation is not valid and the quantization matrix is valid, the quantization is performed. A scale factor using a matrix is derived, the first scaling is performed on the conversion coefficient using the shift value and the scale factor, and the secondary conversion is effective and the quantization matrix is used in the second scaling section. When is valid, a scale factor using a quantization matrix is derived, and the above scale factor is used to perform a second scaling on the conversion coefficient.

In order to solve the above problems, the moving image coding device according to one aspect of the present invention is an image coding device that converts each coefficient after conversion of the prediction error for each conversion unit to derive the conversion coefficient. The first conversion unit that applies the core conversion to the prediction error, the second scaling unit that scales the coefficient after the conversion by the first conversion unit, and the scaling unit after scaling by the scaling unit. It is characterized by including a second conversion unit that applies a secondary conversion to the conversion coefficient, and a first scaling unit that scales the coefficient after conversion by the second conversion unit.

It is the schematic which shows the structure of the image transmission system which concerns on this embodiment. It is a figure which showed the structure of the transmission device which carried out the moving image coding device which concerns on this embodiment, and the receiving device which carried out moving image decoding device. PROD_A indicates a transmitting device equipped with a moving image encoding device, and PROD_B indicates a receiving device equipped with a moving image decoding device. It is a figure which showed the structure of the recording device which carried out the moving image coding device which concerns on this embodiment, and the reproduction device which carried out moving image decoding device. PROD_C indicates a recording device equipped with a moving image encoding device, and PROD_D indicates a playback device equipped with a moving image decoding device. It is a figure which shows the hierarchical structure of the data of a coded stream. It is a figure which shows the division example of CTU. It is a schematic diagram which shows the type (mode number) of an intra prediction mode. It is a schematic diagram which shows the structure of the moving image decoding apparatus. It is a flowchart explaining the schematic operation of the moving image decoding apparatus. It is the schematic which shows the structure of the intra prediction parameter decoding unit. It is a figure which shows the reference area used for intra prediction. It is a figure which shows the structure of the intra prediction image generation part. It is a functional block diagram which shows the structural example of the inverse quantization / inverse conversion part. It is a figure for demonstrating an example of the area to be the target of the inverse secondary conversion. It is a figure for demonstrating an example of the inverse secondary conversion by the inverse secondary conversion part. It is a figure for demonstrating an example of the area to be the target of the inverse secondary transformation in the modification. It is a block diagram which shows the structure of the moving image coding apparatus. It is the schematic which shows the structure of the intra prediction parameter coding part. It is a figure explaining an example of a quantization matrix (scaling list). It is a figure for demonstrating the syntax structure of the quantization matrix (scaling list). It is a block diagram which shows the inverse quantization / inverse conversion part of the 1st structure of this embodiment. It is a flowchart which shows the schematic process of the inverse quantization / inverse conversion part of the 1st configuration of this embodiment. It is a flowchart which shows the detailed processing of the inverse quantization / inverse conversion part of the 1st configuration of this embodiment. It is a block diagram which shows the inverse quantization / inverse conversion part of the 2nd structure of this embodiment. It is a flowchart which shows the schematic process of the inverse quantization / inverse conversion part of the 2nd configuration of this embodiment. It is a flowchart which shows the schematic process of the inverse quantization / inverse conversion part of the 2nd configuration of this embodiment. It is a flowchart which shows the detailed processing of the inverse quantization / inverse conversion part of the 2nd configuration of this embodiment. It is a block diagram which shows the inverse quantization / inverse conversion part of the 3rd structure of this embodiment. It is a flowchart which shows the schematic process of the inverse quantization / inverse conversion part of the 3rd configuration of this embodiment. It is a flowchart which shows the detailed processing of the inverse quantization / inverse conversion part of the 3rd configuration of this embodiment. It is a flowchart which shows the schematic process of the conversion / quantization part of the 1st configuration of this embodiment. It is a flowchart which shows the schematic process of the conversion / quantization part of the 2nd configuration of this embodiment. It is a flowchart which shows the schematic process of the conversion / quantization part of the 3rd configuration of this embodiment.

[Embodiment 1]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view showing a configuration of an image transmission system 1 according to the present embodiment.

The image transmission system 1 is a system that transmits a coded stream in which a coded image is encoded, decodes the transmitted coded stream, and displays an image. The image transmission system 1 includes a moving image coding device (image coding device) 11, a network 21, a moving image decoding device (image decoding device) 31, and an image display device (image display device) 41.

The image T is input to the moving image coding device 11.

The network 21 transmits the coded stream Te generated by the moving image coding device 11 to the moving image decoding device 31. The network 21 is an Internet (Internet), a wide area network (WAN: Wide Area Network), a small network (LAN: Local Area Network), or a combination thereof. The network 21 is not necessarily limited to a two-way communication network, but may be a one-way communication network that transmits broadcast waves such as terrestrial digital broadcasting and satellite broadcasting. Further, the network 21 may be replaced with a storage medium such as a DVD (Digital Versatile Disc: registered trademark) or BD (Blue-ray Disc: registered trademark) on which an encoded stream Te is recorded.

The moving image decoding device 31 decodes each of the coded streams Te transmitted by the network 21 and generates one or a plurality of decoded images Td.

The image display device 41 displays all or a part of one or a plurality of decoded images Td generated by the moving image decoding device 31. The image display device 41 includes display devices such as a liquid crystal display and an organic EL (Electro-luminescence) display, for example. Examples of the display form include stationary, mobile, and HMD. Further, when the moving image decoding device 31 has a high processing capacity, an image having a high image quality is displayed, and when the moving image decoding device 31 has a lower processing capacity, an image which does not require a high processing capacity and a display capacity is displayed. ..

<Operator>
The operators used herein are described below.

>> is the right bit shift, << is the left bit shift, & is the bitwise AND, | is the bitwise OR, | = is the OR assignment operator, and || is the OR.

x? y: z is a ternary operator that takes y when x is true (other than 0) and z when x is false (0).

Clip3 (a, b, c) is a function that clips c to a value greater than or equal to a and less than or equal to b, returning a if c <a, returning b if c> b, and other cases. Is a function that returns c (where a <= b).

abs (a) is a function that returns the absolute value of a.

Int (a) is a function that returns an integer value of a.

floor (a) is a function that returns the smallest integer less than or equal to a.

ceil (a) is a function that returns the largest integer greater than or equal to a.

a / d represents the division of a by d (rounded down to the nearest whole number).

<Structure of coded stream Te>
Prior to the detailed description of the moving image coding device 11 and the moving image decoding device 31 according to the present embodiment, the data of the coded stream Te generated by the moving image coding device 11 and decoded by the moving image decoding device 31. The structure will be described.

FIG. 4 is a diagram showing a hierarchical structure of data in the coded stream Te. The coded stream Te typically includes a sequence and a plurality of pictures that make up the sequence. In FIG. 4, the coded video sequence that defines the sequence SEQ, the coded picture that defines the picture PICT, the coded slice that defines the slice S, the coded slice data that defines the slice data, and the coded slice data, respectively. A diagram showing a coded tree unit included and a coded unit included in the coded tree unit is shown.

(Encoded video sequence)
The coded video sequence defines a set of data that the moving image decoding device 31 refers to in order to decode the sequence SEQ to be processed. The sequence SEQ includes a video parameter set (Video Parameter Set), a sequence parameter set SPS (Sequence Parameter Set), a picture parameter set PPS (Picture Parameter Set), a picture PICT, and a picture PICT, as shown in the encoded video sequence of FIG. Includes Supplemental Enhancement Information (SEI).

The video parameter set VPS defines a set of coding parameters common to a plurality of images and a set of coding parameters related to a plurality of layers included in the image and each layer in an image composed of a plurality of layers. Has been done.

The sequence parameter set SPS defines a set of coding parameters that the moving image decoding device 31 refers to in order to decode the target sequence. For example, the width and height of the picture are specified. In addition, there may be a plurality of SPS. In that case, select one of multiple SPSs from PPS.

The picture parameter set PPS defines a set of coding parameters that the moving image decoding device 31 refers to in order to decode each picture in the target sequence. For example, the quantization width reference value (pic_init_qp_minus26) used for decoding the picture, the flag (weighted_pred_flag) indicating the application of the weighted prediction, and the scaling list (quantization matrix) are included. There may be a plurality of PPSs. In that case, one of a plurality of PPSs is selected from each picture in the target sequence.

(Encoded picture)
The coded picture defines a set of data referred to by the moving image decoding device 31 in order to decode the picture PICT to be processed. The picture PICT includes slices 0 to NS-1 as shown in the encoded picture in FIG. 4 (NS is the total number of slices contained in the picture PICT).

In the following, when it is not necessary to distinguish between slice 0 and slice NS-1, the subscripts of the symbols may be omitted. The same applies to the data included in the coded stream Te described below and with subscripts.

(Coded slice)
The coded slice defines a set of data referred to by the moving image decoding device 31 in order to decode the slice S to be processed. The slice contains a slice header and slice data, as shown in the coded slice of FIG.

The slice header contains a group of coding parameters referred to by the moving image decoding device 31 to determine the decoding method of the target slice. The slice type specification information (slice_type) that specifies the slice type is an example of the coding parameters included in the slice header.

The slice types that can be specified by the slice type specification information include (1) I slices that use only intra-prediction during coding, and (2) P-slices that use unidirectional prediction or intra-prediction during coding. (3) Examples thereof include a B slice that uses unidirectional prediction, bidirectional prediction, or intra prediction at the time of coding. Note that the inter-prediction is not limited to single prediction and bi-prediction, and a prediction image may be generated using more reference pictures. Hereinafter, when referred to as P and B slices, they refer to slices containing blocks for which inter-prediction can be used.

The slice header may include a reference (pic_parameter_set_id) to the picture parameter set PPS.

(Coded slice data)
The coded slice data defines a set of data referred to by the moving image decoding device 31 in order to decode the slice data to be processed. The slice data contains a CTU, as shown in the encoded slice header of FIG. A CTU is a fixed-size (for example, 64x64) block that constitutes a slice, and is sometimes called a maximum coding unit (LCU: Largest Coding Unit).

(Encoded tree unit)
The coded tree unit of FIG. 4 defines a set of data referred to by the moving image decoding device 31 in order to decode the CTU to be processed. CTU is the basis of coding processing by recursive quadtree division (QT (Quad Tree) division), binary tree division (BT (Binary Tree) division) or ternary tree division (TT (Ternary Tree) division). It is divided into a coding unit CU, which is a typical unit. The combination of BT division and TT division is called multi-tree division (MT (Multi Tree) division). A tree-structured node obtained by recursive quadtree division is called a coding node. The intermediate nodes of the quadtree, binary, and ternary tree are coded nodes, and the CTU itself is defined as the highest level coded node.

As CT information, CT includes a QT division flag (cu_split_flag) indicating whether or not to perform QT division, an MT division flag (split_mt_flag) indicating the presence or absence of MT division, and an MT division direction (split_mt_dir) indicating the division direction of MT division. Includes MT split type (split_mt_type) indicating the split type of MT split. cu_split_flag, split_mt_flag, split_mt_dir, split_mt_type are transmitted for each encoding node.

When cu_split_flag is 1, the coded node is split into 4 coded nodes (QT in Figure 5).

When cu_split_flag is 0, when split_mt_flag is 0, the coded node is not divided and has one CU as a node (no division in Fig. 5). The CU is the terminal node of the encoding node and is not divided any further. CU is a basic unit of coding processing.

When split_mt_flag is 1, the encoding node is MT split as follows. When split_mt_type is 0, the coded node is horizontally divided into two coded nodes when split_mt_dir is 1 (BT (horizontal split) in Fig. 5), and when split_mt_dir is 0, the coded node is coded in two. It is vertically divided into nodes (BT (vertical division) in Fig. 5). Also, when split_mt_type is 1, the coding node is horizontally divided into 3 coding nodes when split_mt_dir is 1 (TT (horizontal division) in Fig. 5), and when split_mt_dir is 0, there are 3 coding nodes. It is vertically divided into coding nodes (TT (vertical division) in Fig. 5). These are shown in the CT information in FIG.

If the CTU size is 64x64 pixels, the CU size is 64x64 pixels, 64x32 pixels, 32x64 pixels, 32x32 pixels, 64x16 pixels, 16x64 pixels, 32x16 pixels, 16x32 pixels, 16x16 pixels, 64x8 pixels, 8x64 pixels. , 32x8 pixels, 8x32 pixels, 16x8 pixels, 8x16 pixels, 8x8 pixels, 64x4 pixels, 4x64 pixels, 32x4 pixels, 4x32 pixels, 16x4 pixels, 4x16 pixels, 8x4 pixels, 4x8 pixels, and 4x4 pixels. ..

(Encoding unit)
As shown in the coding unit of FIG. 4, a set of data referred to by the moving image decoding device 31 in order to decode the coding unit to be processed is defined. Specifically, the CU is composed of a CU header CUH, a prediction parameter, a conversion parameter, a quantization conversion coefficient, and the like. The CU header defines the prediction mode and so on.

The prediction process may be performed in CU units or in sub-CU units that are further divided CUs. If the size of the CU and the sub CU are equal, there is only one sub CU in the CU. If the CU is larger than the size of the sub CU, the CU is split into sub CUs. For example, if the CU is 8x8 and the sub CU is 4x4, the CU is divided into 4 sub CUs consisting of 2 horizontal divisions and 2 vertical divisions.

There are two types of prediction (prediction mode): intra-prediction and inter-prediction. Intra prediction refers to prediction within the same picture, and inter prediction refers to prediction processing performed between different pictures (for example, between display times and between layer images).

The conversion / quantization process is performed in CU units, but the quantization conversion coefficient may be entropy-encoded in subblock units such as 4x4.

(Prediction parameter)
The prediction image is derived by the prediction parameters associated with the block. Prediction parameters include intra-prediction and inter-prediction prediction parameters.

Hereinafter, the prediction parameters of the intra prediction will be described. The intra prediction parameters are composed of the luminance prediction mode IntraPredModeY and the color difference prediction mode IntraPredModeC. FIG. 6 is a schematic diagram showing the types (mode numbers) of the intra prediction modes. As shown in FIG. 6, there are 67 types (0 to 66) of intra prediction modes, for example. For example, planar prediction (0), DC prediction (1), Angular prediction (2-66). In addition, LM modes (67-72) may be added for color difference.

Syntax elements for deriving intra prediction parameters include, for example, intra_luma_mpm_flag, intra_luma_mpm_idx, intra_luma_mpm_remainder and the like.

(MPM)
intra_luma_mpm_flag is a flag indicating whether or not IntraPredModeY and MPM (Most Probable Mode) of the target block match. MPM is a prediction mode included in the MPM candidate list mpmCandList []. The MPM candidate list is a list that stores candidates that are presumed to have a high probability of being applied to the target block from the intra prediction mode of the adjacent block and the predetermined intra prediction mode. When intra_luma_mpm_flag is 1, the IntraPredModeY of the target block is derived using the MPM candidate list and the index intra_luma_mpm_idx.

IntraPredModeY = mpmCandList [intra_luma_mpm_idx]
(REM)
When intra_luma_mpm_flag is 0, the intra prediction mode is selected from the remaining modes RemIntraPredMode excluding the intra prediction modes included in the MPM candidate list from the entire intra prediction mode. The intra prediction mode that can be selected as the RemIntraPredMode is called "non-MPM" or "REM". RemIntraPredMode is derived using intra_luma_mpm_remainder.

(Configuration of moving image decoding device)
The configuration of the moving image decoding device 31 (FIG. 7) according to the present embodiment will be described.

The moving image decoding device 31 includes an entropy decoding unit 301, a parameter decoding unit (predicted image decoding device) 302, a loop filter 305, a reference picture memory 306, a predicted parameter memory 307, a predicted image generator (predicted image generator) 308, and a reverse. It is composed of a quantization / inverse conversion unit 311 and an addition unit 312. In addition, there is also a configuration in which the loop filter 305 is not included in the moving image decoding device 31 in accordance with the moving image coding device 11 described later.

The parameter decoding unit 302 further includes a header decoding unit 3020, a CT information decoding unit 3021, and a CU decoding unit 3022 (prediction mode decoding unit), and the CU decoding unit 3022 includes a TU decoding unit 3024. These may be generically called a decoding module. The header decoding unit 3020 decodes the parameter set information such as VPS, SPS, PPS, and the slice header (slice information) from the encoded data. The CT information decoding unit 3021 decodes the CT from the encoded data. The CU decoding unit 3022 decodes the CU from the encoded data. The TU decoding unit 3024 decodes the QP update information (quantization correction value) and the quantization prediction error (residual_coding) from the coded data when the TU contains a prediction error.

The TU decoding unit 3024 decodes the value stIdx indicating the use of the secondary conversion and the conversion basis from the encoded data. Specifically, in the TU decoding unit 3024, the width and height of the CU are 4 or more, the prediction mode is the intra mode, and the number of conversion coefficients in the CU numSigCoeff is a predetermined number THSt (for example). , SINGLE_TREE is 2, otherwise 1) Decrypts stIdx. When stIdx is 0, it indicates that the secondary conversion is not applied, when it is 1, it indicates the conversion of one of the set (pair) of the secondary conversion basis, and when it is 2, it indicates the conversion of the other of the above pairs.

Further, the parameter decoding unit 302 includes an inter-prediction parameter decoding unit 303 and an intra-prediction parameter decoding unit 304 (not shown). The prediction image generation unit 308 includes an inter prediction image generation unit 309 and an intra prediction image generation unit 310.

In the following, an example in which CTU and CU are used as the processing unit will be described, but the processing is not limited to this example, and processing may be performed in sub-CU units. Alternatively, CTU and CU may be read as blocks, sub-CUs may be read as sub-blocks, and processing may be performed in units of blocks or sub-blocks.

The entropy decoding unit 301 performs entropy decoding on the coded stream Te input from the outside, separates and decodes each code (syntax element). For entropy coding, a method of variable-length coding of syntax elements using a context (probability model) adaptively selected according to the type of syntax elements and the surrounding situation, a predetermined table, or There is a method of variable-length coding the syntax element using a calculation formula. The former CABAC (Context Adaptive Binary Arithmetic Coding) stores a stochastic model updated for each encoded or decoded picture (slice) in memory. Then, as the initial state of the context of the P picture or the B picture, the probability model of the picture using the same slice type and the same slice level quantization parameter is set from the probability models stored in the memory. This initial state is used for encoding and decoding processing. The separated codes include prediction information for generating a prediction image, prediction error for generating a difference image, and the like.

The entropy decoding unit 301 outputs the separated codes to the parameter decoding unit 302. The separated code is, for example, the prediction mode predMode. The control of which code is decoded is performed based on the instruction of the parameter decoding unit 302.

(Basic flow)
FIG. 8 is a flowchart illustrating a schematic operation of the moving image decoding device 31.

(S1100: Parameter set information decoding) The header decoding unit 3020 decodes the parameter set information such as VPS, SPS, and PPS from the encoded data.

(S1200: Decoding of slice information) The header decoding unit 3020 decodes the slice header (slice information) from the encoded data.

Hereinafter, the moving image decoding device 31 derives a decoded image of each CTU by repeating the processes of S1300 to S5000 for each CTU included in the target picture.

(S1300: CTU information decoding) The CT information decoding unit 3021 decodes the CTU from the encoded data.

(S1400: CT information decoding) The CT information decoding unit 3021 decodes the CT from the encoded data.

(S1500: CU decoding) The CU decoding unit 3022 executes S1510 and S1520 to decode the CU from the encoded data.

(S1510: CU information decoding) The CU decoding unit 3022 decodes CU information, prediction information, TU division flag split_transform_flag, CU residual flags cbf_cb, cbf_cr, cbf_luma, etc. from the encoded data.

(S1520: TU information decoding) When the TU contains a prediction error, the TU decoding unit 3024 decodes the QP update information (quantization correction value) and the quantization prediction error (residual_coding) from the encoded data. The QP update information is a difference value from the quantization parameter prediction value qPpred, which is the prediction value of the quantization parameter QP.

(S2000: Prediction image generation) The prediction image generation unit 308 generates a prediction image based on the prediction information for each block included in the target CU.

(S3000: Inverse quantization / inverse conversion) Inverse quantization / inverse conversion unit 311 executes inverse quantization / inverse conversion processing for each TU included in the target CU.

(S4000: Decoded image generation) The addition unit 312 decodes the target CU by adding the prediction image supplied by the prediction image generation unit 308 and the prediction error supplied by the inverse quantization / inverse conversion unit 311. Generate an image.

(S5000: Loop filter) The loop filter 305 applies a loop filter such as a deblocking filter, SAO, or ALF to the decoded image to generate a decoded image.

(Quantization matrix)
The quantization matrix means a method of performing different quantization / inverse quantization depending on the position of the conversion coefficient, and a matrix used for quantization. Quantization / dequantization is also called scaling, and the quantization matrix is also called a scaling list or scaling factor. By using the quantization matrix, the high frequency component can be made smaller (it tends to be 0), and the coding rate can be reduced while suppressing the deterioration of the subjective image quality. Further, the image quality can be adjusted by adjusting the ratio of the high frequency component to the low frequency component and the ratio of the horizontal component, the vertical component, and the diagonal component.

The parameter decoding unit 302 includes a scaling list decoding unit (not shown).

FIG. 18 shows an example of a quantization matrix (scaling list, scaling factor). Here are examples of ScalingFactor2 [8] [8] [0] [x] [y], x = 0.7, y = 0.7 for the 8x8 conversion coefficient array d [x] [y]. ..

FIG. 19 shows the syntax configuration of the scaling list.

The scaling list decoding unit decodes the scaling_list_enabled_flag indicating whether or not to use the quantization matrix from the encoded data. When scaling_list_enabled_flag is 1, the scaling list is used in the scaling process described later.

The scaling list decoding unit decodes the scaling list information called scaling_list_data () from the encoded data to derive a quantization matrix. Further, the scaling list decoding unit may use a predetermined matrix (default matrix) without decoding from the encoded data.

The scaling list decoding unit decodes the scaling list ScalingList [sizeId] [matrixId] [i] represented by the size sizeId and the matrix identifier matrixId. sizeId = 0,1,2,3,4,5,6 correspond to 1x1, 2x2, 4x4, 8x8, 16x16, 32x32, 64x64, respectively. matrixId = 0, 1, 2, 3, 4, 5 are the brightness of the intra prediction (cIdx == 0), the Cb of the intra prediction (cIdx == 1), the Cr of the intra prediction (cIdx == 2), and the inter. It may correspond to the predicted brightness (cIdx == 0), the inter-prediction Cb (cIdx == 1), and the inter-prediction Cr (cIdx == 2). For example, the scaling list decoding unit decodes the flags scaling_list_pred_mode_flag [sizeId] [matrixId] indicating whether to predict or decode the scaling list. When predicting the scaling list, the difference value scaling_list_dc_coef_minus8 [sizeId-4] [matrixId] of the scaling list is decoded, and when decoding the scaling list, the coefficient value scaling_list_dc_coef_minus8 [sizeId-4] [matrixId] of the scaling list is decoded. May be good.

The scaling list decoding unit derives nextCoef from the decoded syntax value, and calculates the ScalingList [sizeId] [matrixId] [i] for each position i in the array d [] [] of sizeId, matrixId, and conversion coefficients. Derived.

nextCoef = scaling_list_dc_coef_minus8 [sizeId-4] [matrixId] + 8
nextCoef = (nextCoef + scaling_list_delta_coef + 256)% 256
ScalingList [sizeId] [matrixId] [i] = nextCoef
Further, when scaling_list_pred_mode_flag is 1, the scaling list decoding unit may make a prediction by referring to the existing scaling list referred to by refMatrixId as shown below.

refMatrixId = matrixId --scaling_list_pred_matrix_id_delta [sizeId] [matrixId]
ScalingList [sizeId] [matrixId] [i] = ScalingList [sizeId] [refMatrixId] [i]
Where i = 0..Min (63, (1 << (sizeId << 1)) ―― 1)
The scaling list decoding unit uses the derived ScalingList [sizeId] [matrixId] [i], and further, for each position (x, y) in the array d [x] [y] of sizeId, matrixId, and conversion coefficients. , ScalingFactor [sizeId] [matrixId] [x] [y] may be derived. For example, in the case of 4x4, it is derived as follows.

ScalingFactor [2] [matrixId] [x] [y] = ScalingList [2] [matrixId] [i]
x = DiagScanOrder [2] [2] [i] [0]
y = DiagScanOrder [2] [2] [i] [1]
Where i = 0..15, matrixId = 0..5.

For example, in the case of 8x8, it is derived as follows.

ScalingFactor [3] [matrixId] [x] [y] = ScalingList [3] [matrixId] [i]
x = DiagScanOrder [3] [3] [i] [0]
y = DiagScanOrder [3] [3] [i] [1]
Where i = 0..63, matrixId = 0..5.

DiagScanOrder [sizeId] [sizeId] [i] [j] is an array indicating the scanning order in a block (array) having a width of 1 << sizeId and a height of 1 << sizeId.

Further, the scaling list decoding unit derives the quantization matrix ScalingFactor2 [sizeIdW] [sizeIdH] [matrixId] [x] [y] used for scaling the conversion coefficient block (TU) other than the square by the following equation. sizeIdW and sizeIdH indicate the width (1 << sizeIdW) and height (1 << sizeIdH) of the conversion coefficient block.

ScalingFactor2 [sizeIdW] [sizeIdH] [matrixId] [x] [y] = ScalingFactor [sizeId] [matrixId] [x * ratioW] [y * ratioH]
sizeId = max (sizeIdW, sizeIdH)
ratioW = (1 << sizeId) / (1 << sizeIdW)
ratioH = (1 << sizeId) / (1 << sizeIdH)
Where sizeIdW = 0..6, sizeIdH = 0..6, matrixId = 0..5, x = 0 .. (1 << sizeIdW) -1, y = 0 .. (1 << sizeIdH)- It is 1. Note that (sizeIdW, sizeIdH) = (0, 0) is not used.

Further, the parameter decoding unit 302 includes an inter-prediction parameter decoding unit 303 and an intra-prediction parameter decoding unit 304 (not shown). The prediction image generation unit 308 includes an inter-prediction image generation unit 309 and an intra-prediction image generation unit 310 (not shown).

(Structure of Intra Prediction Parameter Decoding Unit 304)
The intra prediction parameter decoding unit 304 decodes the intra prediction parameter, for example, the intrapred mode, with reference to the prediction parameter stored in the prediction parameter memory 307, based on the code input from the entropy decoding unit 301. The intra prediction parameter decoding unit 304 outputs the decoded intra prediction parameter to the prediction image generation unit 308, and stores it in the prediction parameter memory 307. The intra prediction parameter decoding unit 304 may derive an intra prediction mode that differs depending on the brightness and the color difference.

FIG. 9 is a schematic view showing the configuration of the intra-prediction parameter decoding unit 304 of the parameter decoding unit 302. As shown in FIG. 9, the intra prediction parameter decoding unit 304 includes a parameter decoding control unit 3041, a luminance intra prediction parameter decoding unit 3042, and a color difference intra prediction parameter decoding unit 3043.

The parameter decoding control unit 3041 instructs the entropy decoding unit 301 to decode the syntax element, and receives the syntax element from the entropy decoding unit 301. When the intra_luma_mpm_flag is 1, the parameter decoding control unit 3041 outputs intra_luma_mpm_idx to the MPM parameter decoding unit 30422 in the luminance intra prediction parameter decoding unit 3042. When the intra_luma_mpm_flag is 0, the parameter decoding control unit 3041 outputs the intra_luma_mpm_remainder to the non-MPM parameter decoding unit 30423 of the luminance intra prediction parameter decoding unit 3042. Further, the parameter decoding control unit 3041 outputs the syntax element of the color difference intra prediction parameter to the color difference intra prediction parameter decoding unit 3043.

The luminance intra prediction parameter decoding unit 3042 includes an MPM candidate list derivation unit 30421, an MPM parameter decoding unit 30422, and a non-MPM parameter decoding unit 30423 (decoding unit, derivation unit).

The MPM parameter decoding unit 30422 derives the IntraPredModeY by referring to the mpmCandList [] and the intra_luma_mpm_idx derived by the MPM candidate list derivation unit 30421, and outputs the IntraPredModeY to the intra prediction image generation unit 310.

The non-MPM parameter decoding unit 30423 derives RemIntraPredMode from mpmCandList [] and intra_luma_mpm_remainder, and outputs IntraPredModeY to the intra prediction image generation unit 310.

The color difference intra prediction parameter decoding unit 3043 derives IntraPredModeC from the syntax element of the color difference intra prediction parameter and outputs it to the intra prediction image generation unit 310.

The loop filter 305 is a filter provided in the coding loop, which removes block distortion and ringing distortion to improve image quality. The loop filter 305 applies filters such as a deblocking filter, a sample adaptive offset (SAO), and an adaptive loop filter (ALF) to the decoded image of the CU generated by the addition unit 312.

The reference picture memory 306 stores the decoded image of the CU generated by the addition unit 312 at a predetermined position for each target picture and the target CU.

The prediction parameter memory 307 stores the prediction parameters at a predetermined position for each CTU or CU to be decoded. Specifically, the prediction parameter memory 307 stores the parameters decoded by the parameter decoding unit 302 and the pred mode and the like separated by the entropy decoding unit 301.

PredMode, prediction parameters, etc. are input to the prediction image generation unit 308. Further, the prediction image generation unit 308 reads the reference picture from the reference picture memory 306. The prediction image generation unit 308 generates a prediction image of a block or a subblock by using the prediction parameter and the read reference picture (reference picture block) in the prediction mode indicated by predMode. Here, the reference picture block is a set of pixels on the reference picture (usually called a block because it is rectangular), and is an area to be referred to for generating a predicted image.

(Intra prediction image generation unit 310)
When the predMode indicates the intra prediction mode, the intra prediction image generation unit 310 performs the intra prediction using the intra prediction parameters input from the intra prediction parameter decoding unit 304 and the reference pixels read from the reference picture memory 306.

Specifically, the intra prediction image generation unit 310 reads an adjacent block on the target picture within a predetermined range from the target block from the reference picture memory 306. The predetermined range is adjacent blocks on the left, upper left, upper, and upper right of the target block, and the area to be referred to differs depending on the intra prediction mode.

The intra prediction image generation unit 310 generates a prediction image of the target block by referring to the read decoding pixel value and the prediction mode indicated by IntraPredMode. The intra prediction image generation unit 310 outputs the prediction image of the generated block to the addition unit 312.

The generation of the predicted image based on the intra prediction mode will be described below. In Planar prediction, DC prediction, and Angular prediction, the decoded peripheral area adjacent (proximity) to the prediction target block is set as the reference area R. Then, the predicted image is generated by extrapolating the pixels on the reference region R in a specific direction. For example, the reference area R is an L-shaped area including the left and top of the prediction target block (or further, upper left, upper right, lower left) (for example, the pixels marked with diagonal circles in Example 1 of the reference area in FIG. It may be set as the area shown).

(Details of the predicted image generator)
Next, the details of the configuration of the intra prediction image generation unit 310 will be described with reference to FIG. The intra prediction image generation unit 310 includes a prediction target block setting unit 3101, an unfiltered reference image setting unit 3102 (first reference image setting unit), a filtered reference image setting unit 3103 (second reference image setting unit), and an intra. It includes a prediction unit 3104 and a prediction image correction unit 3105 (prediction image correction unit, filter switching unit, weight coefficient changing unit).

Based on each reference pixel (unfiltered reference image) on the reference area R, the filtered reference image generated by applying the reference pixel filter (first filter), and the intra prediction mode, the intra prediction unit 3104 is a prediction target block. (Prediction image before correction) is generated and output to the prediction image correction unit 3105. The prediction image correction unit 3105 corrects the provisional prediction image according to the intra prediction mode, generates a prediction image (corrected prediction image), and outputs the prediction image.

Hereinafter, each unit included in the intra prediction image generation unit 310 will be described.

(Prediction target block setting unit 3101)
The prediction target block setting unit 3101 sets the target CU as the prediction target block, and outputs information (prediction target block information) regarding the prediction target block. The prediction target block information includes at least an index indicating the size, position, brightness or color difference of the prediction target block.

(Unfiltered reference image setting unit 3102)
The unfiltered reference image setting unit 3102 sets the adjacent peripheral area of the prediction target block as the reference area R based on the size and position of the prediction target block. Subsequently, each pixel value (unfiltered reference image, boundary pixel) in the reference area R is set with each decoded pixel value at the corresponding position on the reference picture memory 306. The line r [x] [-1] of the decoding pixels adjacent to the upper side of the prediction target block shown in Example 1 of the reference area of FIG. ] Is an unfiltered reference image.

(Filtered reference image setting unit 3103)
The filtered reference image setting unit 3103 applies a reference pixel filter (first filter) to the unfiltered reference image according to the intra prediction mode, and filters each position (x, y) on the reference area R. Derivation of the reference image s [x] [y]. Specifically, a low-pass filter is applied to the unfiltered reference image at the position (x, y) and its surroundings, and the filtered reference image (example 2 of the reference area in FIG. 10) is derived. It is not always necessary to apply the low-pass filter to all the intra-prediction modes, and the low-pass filter may be applied to some of the intra-prediction modes. In the filtered reference image setting unit 3103, the filter applied to the unfiltered reference image on the reference area R is called a "reference pixel filter (first filter)", whereas in the prediction image correction unit 3105 described later. A filter that corrects a tentatively predicted image is called a "boundary filter (second filter)".

(Structure of Intra Prediction Unit 3104)
The intra prediction unit 3104 generates a tentative prediction image (provisional prediction pixel value, pre-correction prediction image) of the prediction target block based on the intra prediction mode, the unfiltered reference image, and the filtered reference pixel value, and the prediction image correction unit Output to 3105. The intra prediction unit 3104 includes a Planar prediction unit 31041, a DC prediction unit 31042, an Angular prediction unit 31043, and an LM prediction unit 31044 inside. The intra prediction unit 3104 selects a specific prediction unit according to the intra prediction mode, and inputs an unfiltered reference image and a filtered reference image. The relationship between the intra prediction mode and the corresponding prediction unit is as follows.
・ Planar Prediction ・ ・ ・ Planar Prediction Department 31041
・ DC prediction ・ ・ ・ DC prediction unit 31042
・ Angular Prediction ・ ・ ・ Angular Prediction Department 31043
・ LM prediction ・ ・ ・ LM prediction unit 31044
(Planar forecast)
The Planar prediction unit 31041 linearly adds a plurality of filtered reference images according to the distance between the prediction target pixel position and the reference pixel position to generate a tentative prediction image, and outputs the provisional prediction image to the prediction image correction unit 3105.

(DC prediction)
The DC prediction unit 31042 derives a DC prediction value corresponding to the average value of the filtered reference images s [x] [y], and outputs a provisional prediction image q [x] [y] using the DC prediction value as a pixel value. To do.

(Angular prediction)
The Angular prediction unit 31043 generates a tentative prediction image q [x] [y] using the filtered reference images s [x] [y] in the prediction direction (reference direction) indicated by the intra prediction mode, and the prediction image correction unit. Output to 3105.

(LM prediction)
The LM prediction unit 31044 predicts the pixel value of the color difference based on the pixel value of the luminance. Specifically, it is a method of generating a predicted image of a color difference image (Cb, Cr) using a linear model based on a decoded luminance image. CCLM (Cross-Component Linear Model prediction) prediction, which is one of the LM predictions, is a prediction method that uses a linear model for predicting the color difference from the luminance for one block.

(Structure of Prediction Image Correction Unit 3105)
The prediction image correction unit 3105 corrects the tentative prediction image output from the intra prediction unit 3104 according to the intra prediction mode. Specifically, the prediction image correction unit 3105 weights and adds the unfiltered reference image and the provisional prediction image to each pixel of the provisional prediction image according to the distance between the reference region R and the target prediction pixel (weighted average). By doing so, the predicted image (corrected predicted image) Pred obtained by modifying the provisional predicted image is derived. In some intra-prediction modes, the prediction image correction unit 3105 may not correct the provisional prediction image, and the output of the intra-prediction unit 3104 may be used as the prediction image as it is.

(Inverse quantization / inverse conversion unit 311)
The inverse quantization / inverse conversion unit 311 inversely quantizes the quantization conversion coefficient qd [] [] input from the entropy decoding unit 301 to obtain the conversion coefficient d [] []. This quantization transform coefficient qd [] [] performs frequency transformation such as DCT (Discrete Cosine Transform) and DST (Discrete Sine Transform) on the prediction error in the coding process. It is a coefficient obtained by transforming. The inverse quantization / inverse conversion unit 311 performs inverse frequency conversion such as inverse DCT and inverse DST on the obtained conversion coefficient, and calculates a prediction error. The inverse quantization / inverse conversion unit 311 outputs the prediction error to the addition unit 312.

Hereinafter, a configuration example of the inverse quantization / inverse conversion unit 311 will be described with reference to FIG. FIG. 12 is a functional block diagram showing a configuration example of the inverse quantization / inverse conversion unit 311. As shown in FIG. 12, the quantization / inverse conversion unit 311 includes an inverse quantization unit 3111 and an inverse conversion unit 3112. The inverse quantization unit 3111 dequantizes the quantization conversion coefficient qd [] [] decoded by the TU decoding unit 3024, and derives the conversion coefficient d [] []. The inverse quantization unit 3111 outputs the derived conversion coefficient d [] [] to the inverse conversion unit 3112.

The inverse conversion unit 3112 reversely converts the received conversion coefficient d [] [] for each conversion unit TU, and restores the prediction error r [] []. The inverse conversion unit 3112 outputs the restored prediction error r [] [] to the addition unit 312.

The inverse conversion unit 3112 includes an inverse secondary conversion unit (second conversion unit) 31121, a scaling unit 31122, and an inverse core conversion unit (first conversion unit) 31123.

Since the inverse transformation and the transformation are paired processes, the transformation and the inverse transformation may be interpreted by replacing each other. Alternatively, when the inverse transformation is called a transformation, the transformation may be called a forward transformation. For example, when the inverse secondary conversion is called a secondary conversion, the secondary conversion may be called a forward secondary conversion. Also, core conversion is simply called conversion.

(Inverse secondary conversion unit 31121)
The inverse secondary conversion unit (second conversion unit) 31121 applies the inverse secondary conversion to the conversion coefficient d [] [] after the inverse quantization and before the inverse core conversion.

The inverse secondary conversion unit 31121 performs an inverse secondary conversion of the conversion coefficient d [] [] received from the inverse quantization unit 3111 to correct the conversion coefficient (conversion coefficient after conversion by the second conversion unit) d [] [ ] Is restored. The inverse secondary conversion unit 31121 outputs the restored modified conversion coefficient d [] [] to the inverse core conversion unit 31123.

The inverse core conversion unit 31123 acquires the conversion coefficient d [] [] or the correction conversion coefficient d [] [] restored by the inverse secondary conversion unit 31121, performs inverse core conversion, and predicts an error r [] []. Is derived. The inverse core conversion unit 31123 outputs the prediction error r [] [] to the addition unit 312.

The inverse secondary conversion unit 31121 applies the inverse secondary conversion to the conversion coefficient d [] [] of a predetermined unit for each conversion unit TU. The inverse secondary transformation is applied only in the intra CU, and the transformation basis is determined with reference to the intra prediction mode. The selection of the conversion basis will be described later.

(Application example 1 of inverse secondary conversion by inverse secondary conversion unit 31121)
Hereinafter, application example 1 of the inverse secondary conversion by the inverse secondary conversion unit 31121 will be described with reference to FIG. FIG. 13 is a diagram for explaining an example of a region targeted for inverse secondary conversion in the present embodiment.

When the TU is 8 × 8 or more, the inverse secondary conversion unit 31121 applies the inverse secondary conversion only to the conversion coefficients of NUMSTC or less including the lowest frequency component among the conversion coefficients included in the TU.

Here, as a premise for explaining the details of the inverse secondary conversion by the inverse secondary conversion unit 31121 in the present embodiment, first, the secondary conversion and the inverse secondary conversion will be described.

(Explanation of secondary conversion and inverse secondary conversion)
The secondary conversion is applied to the conversion coefficient of a part or all of the TU core conversion (DCT2, DST7, etc.) in the moving image encoding device 11. In the secondary conversion, the correlation remaining in the conversion coefficient is removed and the energy is concentrated on some conversion coefficients. The inverse secondary conversion is applied to the conversion coefficient of a part or all of the TU in the moving image decoding device 31. After the inverse secondary conversion is applied, the inverse core conversion (DCT2, DST7, etc.) is applied to the conversion coefficient after the inverse secondary conversion. Further, when the TU is divided into 4x4 sub-blocks, the secondary conversion and the inverse secondary conversion are applied only to the predetermined sub-block on the upper left. Of the width W and height H of the TU, the size of the TU whose one is 4 is, for example, 4 × 4, 8 × 4, 4 × 8, L × 4 and 4 × L (L is a natural number of 16 or more). Can be mentioned.

In the secondary conversion and the inverse secondary conversion, the following processing is performed according to the size of the TU and the intra prediction mode. Hereinafter, the processing of the inverse secondary conversion will be described in order.

(S1: Setting of conversion size and input / output size)
In inverse secondary conversion, depending on the size of the TU (width W, height H), the size of the inverse secondary conversion (4x4 or 8x8), the number of output conversion factors (nStOutSize), and the conversion factor to be applied (input conversion factor). ) Number nonZeroSize and the number of subblocks (numStX, numStY) to which the inverse secondary transformation is applied are derived. The size of the inverse secondary conversion of 4x4 and 8x8 is indicated by nStSize = 4 and 8. Further, the sizes of the inverse secondary conversions of 4x4 and 8x8 may be referred to as RST4x4 and RST8x8, respectively.

In the inverse secondary conversion, when the TU is larger than a predetermined size, 48 conversion coefficients are output by the inverse secondary conversion of RST8x8. Otherwise, the inverse secondary conversion of RST4x4 outputs 16 conversion coefficients. When the TU is 4x4, 16 conversion coefficients are derived from the conversion coefficient of 8 using RST4x4, and when the TU is 8x8, the conversion coefficient of 48 is derived from the conversion coefficient of 8 using RST8x8. In other cases, 16 or 48 conversion coefficients are output from 16 conversion coefficients depending on the size of the TU.

If both W and H are 8 or more, log2StSize = 3, nStOutSize = 48
Other than the above, log2StSize = 2, nStOutSize = 16
nStSize = 1 << log2StSize
If both W and H are 4, or 8x8, nonZeroSize = 8
Other than the above, nonZeroSize = 16
numStX = (nTbH == 4 &&nTbW> 8)? 2: 1
numStY = (nTbW == 4 &&nTbH> 8)? 2: 1
(S2: Sorted into one-dimensional signal)
In the inverse secondary conversion, a part of the conversion coefficients d [] [] of TU is once rearranged into the one-dimensional array u [] and processed. Specifically, in the inverse secondary transformation, the conversion coefficient of x = 0 .. nonZeroSize-1 is derived from the two-dimensional conversion coefficient d [] [] of the target TU indicated by the region RU, which is the rectangular block of the dotted line in FIG. To derive u [] with reference to. xC and yC are positions on the TU, and the sequence DiagS indicating the scan order
Derived from canOrder and the position x of the conversion factor in the subblock.

xC = (xSbIdx << log2StSize) + DiagScanOrder [log2StSize] [log2StSize] [x] [0]
yC = (ySbIdx << log2StSize) + DiagScanOrder [log2StSize] [log2StSize] [x] [1]
u [x] = d [xC] [yC]
The range copied to the one-dimensional array is called the area RU.

(S3: Application of conversion processing)
In the inverse secondary transformation, u [] (vector F') with a length of nonZeroSize is transformed using the transformation basis (matrix) T1 of the first kind, and the output is a one-dimensional array with a length of nStOutSize. Derivation of the coefficient v'[] (vector V').

This transformation can be expressed by the following equation in matrix operation.

V'= T1 × F'
Here, the conversion basis when the conversion size is 4x4 (RST4x4) is called the first type conversion basis T1. When the conversion size is 8x8 (RST8x8), the conversion basis is called the second type conversion basis T2. T1 is a 16x16 (16 rows 16 columns) matrix, and the transformation is 16x1 (16 rows 1 column) vector V'as the product of 16x16 matrix F'and 16x1 (16 rows 1 column) vector F'. That is, the coefficient v'[] of length 16 is derived. T2 is a 48 × 16 (48 rows 16 columns) matrix, and the transformation is 48 × 1 (48 rows 1 column, length 48) vector V'as the product of the 48x16 matrix F'and the 16x1 vector F', That is, a coefficient v'[] of length 48 is derived.

Specifically, in the inverse secondary conversion, the set number (stTrSetId) of the secondary conversion derived from the intrapred mode IntraPredMode, stIdx indicating the conversion basis of the secondary conversion decoded from the encoded data, and the secondary conversion size nStSize ( From nTrS), the corresponding conversion matrix secTranMatrix [] [] (transformation basis T1 or T2) is derived. Further, in the inverse secondary transformation, the product-sum operation of the transformation matrix and the one-dimensional variable u [] is performed as shown in the following equation.
v [i] = Clip3 (CoeffMin, CoeffMax, ΣsecTransMatrix [j] [i] * u [j])
Here, Σ is the sum up to j = 0..nonZeroSize-1. In addition, i processes 0..nStSize-1. CoeffMin and CoeffMax indicate the range of conversion coefficient values.

(S4: Two-dimensional arrangement of one-dimensional signal after conversion processing)
In the inverse secondary transformation, the coefficient v'[] of the converted one-dimensional array is placed again at a predetermined position in the TU (for example, region R1 in FIG. 13).

In the case of RST4x4, the coefficient v'[] of length 16 is placed in the TU as a 4x4 subblock. The obtained TU is inversely converted. The arrangement method may be changed according to the intra prediction mode (intra prediction direction). For example, if the intra prediction direction is between the lower left diagonal direction and the upper left diagonal direction shown in Fig. 6 (intra prediction mode is 34 or less), 4 coefficients from left to right and 4 times from top to bottom. Repeat and place a coefficient v'[] of length 16. If the intra prediction direction is between the upper left diagonal direction and the upper right diagonal direction shown in Fig. 6 (intra prediction mode is 35 or more), 4 coefficients from top to bottom and 4 times from left to right. Repeat and place a coefficient v'[] of length 16. This gives a 4x4 subblock before core conversion.

In the case of RST8x8, for example, when the intra prediction direction is the direction between the lower left diagonal direction and the upper left diagonal direction shown in FIG. 6 (intra prediction mode is 34 or less), the inverse secondary conversion unit Place 8 coefficients from left to right and repeat this 4 times from top to bottom. Next, 4 coefficients are arranged from left to right, and this is repeated 4 times from top to bottom. In addition, when the direction is between the upper left diagonal direction and the upper right diagonal direction shown in FIG. 6 (intra prediction mode is 35 or more), in the inverse secondary conversion, 8 coefficients are arranged from top to bottom, and this is left. Repeat 4 times to the right. Next, 4 coefficients are arranged from top to bottom, and this is repeated 4 times from left to right.

The example of the conversion residual after dequantization in FIG. 13 shows an example of the conversion residual in which the coefficient v'[] of the converted one-dimensional array is arranged in the process S4. This is also an example of the conversion residual after dequantization (the reference range is the region RU), which is partially referred to as the one-dimensional array u [] in the process S2. In the inverse secondary conversion, a coefficient v'[] having a length of nStOutSize obtained by the above process S3 is placed in the region RU on the upper left side of the conversion coefficient array d [] [].

In the inverse secondary conversion, the following processing is performed for x = 0..nStSize --1, y = 0..nStSize --1.

Specifically, in the inverse secondary conversion, when PredModeIntra <= 34 or INTRA_LT_CCLM, INTRA_T_CCLM, or INTRA_L_CCLM, the following formula is applied.

d [(xSbIdx << log2StSize) + x] [(ySbIdx << log2StSize) + y] =
(y <4)? v [x + (y << log2StSize)]: ((x <4)? V [32 + x + ((y -4) << 2)]:
d [(xSbIdx << log2StSize) + x] [(ySbIdx << log2StSize) + y])
Otherwise, the inverse secondary transformation applies the following equation:
d [(xSbIdx << log2StSize) + x] [(ySbIdx << log2StSize) + y] =
(y <4)? V [x + (y << log2StSize)]: ((x <4)? V [32 + (y -4) + (x << 2)]: d [(xSbIdx << log2StSize)) + x] [(ySbIdx << log2StSize) + y])
In the above process, there are multiple tables for holding the first type of transformation basis T1 represented by RST4 × 4 (16 × 16 matrix) (for example, the product of the number of sets of secondary transformations and the number of secondary index stIdx). , For example, 8) may be used. Similarly, in the above processing, a plurality of tables (for example, eight) for holding the second type of conversion basis T2 represented by RST8 × 8 (48 × 16 matrix) may be used. In this case, the amount of memory required for secondary conversion and inverse secondary conversion is as large as about 8 Kbytes (16 x 16 x 8 + 48 x 16 x 8 = 8192 bytes), and secondary conversion and inverse secondary conversion should be applied appropriately. Can't.

(Explanation of inverse secondary conversion by inverse secondary conversion unit 31121)
In the following, an example in which the number of conversion coefficients (nStOutSize described above) that is the target of inverse secondary conversion is NUMSTC (NUMSTC is less than 48) will be described. When the TU is 8 × 8 or more, the inverse secondary conversion unit 31121 applies the inverse secondary conversion to the NUMSTC conversion coefficients including the lowest frequency component among the conversion coefficients included in the TU. Specifically, the inverse secondary conversion unit 31121 includes the lowest frequency component included in the region RU on the upper left side of the conversion residual after inverse quantization shown in the example of the conversion residual after inverse quantization in FIG. Apply inverse secondary transformation to NUMSTC conversion coefficients. The number of NUMSTCs may be 43 or less, but may be 36 or 32, for example.

In the process S1, the inverse secondary conversion unit 31121 sets log2StSize = 3, StSize = 8, nStOutSize = NUMSTC as one case in the process S1, derives the array u [] of nStOutSize = NUMSTC in the process S3, and then processes. In S4, an array u of length nStOutSize = NUMSTC may be placed in the region.

As a result, the memory of the table required for the secondary conversion and the inverse secondary conversion can be significantly reduced. As a result, the secondary conversion and the inverse secondary conversion can be preferably applied.

The secondary conversion unit (not shown) and the inverse secondary conversion unit 31121 apply the secondary conversion and the inverse secondary conversion in the same manner as in the above example, except for the position and the number of conversion coefficients to be selected.

Hereinafter, the details of the application example 1 of the inverse secondary conversion by the inverse secondary conversion unit 31121 will be described.

(Application example 1-1 of inverse secondary conversion by inverse secondary conversion unit 31121)
An application example 1 of the inverse secondary conversion by the inverse secondary conversion unit 31121 will be described in detail with reference to the conversion coefficient selection example 1 of FIG.

For example, the inverse secondary conversion unit 31121 sets log2StSize = 3, StSize = 8, nStOutSize = NUMSTC as one case in the process S1, and derives the array u [] of nStOutSize = NUMSTC in the process S3. , In process S4, an array u of length nStOutSize = NUMSTC may be placed in region R2. Here, NUMSTC = 36 or 43 may be set.

In this case, first, when the TU is 8 × 8 or more, the secondary conversion unit includes NUMSTCs, for example, 36 NUMSTCs included in the triangular region R2 including the lowest frequency component of the conversion coefficient selection example 1. The transformation coefficients are rearranged into a one-dimensional vector V, a secondary transformation is applied, and an array u [] of length 16 is derived. The inverse secondary conversion unit 31121 applies the inverse secondary transformation to u'[] that has been quantized and inverse quantized to u [], and derives the coefficient v'[]. Then, the inverse secondary conversion unit 31121 rearranges the coefficients v'[] and arranges them in the area R2. In this case, the secondary conversion unit and the inverse secondary conversion unit 31121 apply the second type of conversion basis T2 represented by the NUMSTC × 16 matrix, for example, the 36 × 16 matrix, as RST8 × 8. The conversion coefficient of the region RU that is not included in the region R2 may be retained or may be zeroed out.

As a result, the table memory required for secondary conversion and inverse secondary conversion will be approximately 6.7 Kbytes (16 x 16 x 8 + 36 x 16 x 8 = 6656 bytes), and the memory will be significantly reduced (here, approximately 20%). Can be done. As a result, the secondary conversion and the inverse secondary conversion can be preferably applied.

(Application example 1-2 of inverse secondary conversion by inverse secondary conversion unit 31121)
With reference to the conversion coefficient selection examples 2 and 3 in FIG. 13, only the differences from the application example 1 will be described for the application example 2 of the inverse secondary conversion by the inverse secondary conversion unit 31121.

As shown in the conversion coefficient selection example 2 of FIG. 13, the inverse secondary conversion unit 31121 sets NUMSTC = 32, and in the process S4, the coefficient v'[] of the one-dimensional array having a length of nStOutSize = NUMSTC is set to the region R3. It may be arranged.
If PredModeIntra <= 34 or INTRA_LT_CCLM, INTRA_T_CCLM, or INTRA_L_CCLM, apply the following.
d [(xSbIdx << log2StSize) + x] [(ySbIdx << log2StSize) + y] = v [x + (y << log2StSize)]
Otherwise, apply:
d [(xSbIdx << log2StSize) + x] [(ySbIdx << log2StSize) + y] =
(y <4)? V [x + (y << log2StSize)]: ((x <4)? V [32 + (y -4) + (x << 2)]: d [(xSbIdx << log2StSize)) + x] [(ySbIdx << log2StSize) + y])
Further, as shown in the conversion coefficient selection example 3 of FIG. 13, the inverse secondary conversion unit 31121 sets NUMSTC = 32, and in the process S4, the coefficient v'[] of the one-dimensional array having a length of nStOutSize = NUMSTC is set as a region. It may be placed in R4.

In Application Example 2, the target area for conversion is a rectangle (8 × 4 area R3 or 4 × 8 area R4 including the lowest frequency component). Then the number of conversion coefficients NUMSTC is set to 32. In this case, the secondary conversion unit and the inverse secondary conversion unit 31121 apply the second type of conversion basis T2 represented by the 32 × 16 matrix as RST 8 × 8.

As a result, the table memory required for secondary conversion and inverse secondary conversion will be approximately 6.1 Kbytes (16 x 16 x 8 + 32 x 16 x 8 = 6144 bytes), which will significantly reduce the memory (here, approximately 25%). Can be done. As a result, the secondary conversion and the inverse secondary conversion can be preferably applied.

The inverse secondary conversion unit 31121 has, depending on the conditions, of the 8 × 4 region R3 shown in the conversion coefficient selection example 2 of FIG. 13 and the 4 × 8 region R4 shown in the conversion coefficient selection example 3 of FIG. You may decide which to apply the inverse secondary transformation to.

For example, the inverse secondary conversion unit 31121 may determine which of the regions R3 and R4 the inverse secondary conversion is applied to, depending on the shape of the TU. More specifically, the inverse secondary conversion unit 31121 may decide to apply the inverse secondary conversion to the region R3 when the shape of the TU is W ≧ H. Further, the inverse secondary conversion unit 31121 may decide to apply the inverse secondary conversion to the region R4 when the shape of the TU is W <H.

Further, the inverse secondary conversion unit 31121 may determine which of the regions R3 and R4 the inverse secondary conversion is applied to according to the intra prediction mode. More specifically, the inverse secondary conversion unit 31121 reverses the region R3 when the direction is between the upper left diagonal direction and the upper right diagonal direction shown in FIG. 6 (intra prediction mode is 35 or more). You may decide to apply a secondary transformation. Further, the inverse secondary conversion unit 31121 applies the inverse secondary conversion to the region R4 when the direction is between the lower left diagonal direction and the upper left diagonal direction shown in FIG. 6 (intra prediction mode is 34 or less). You may decide to do so.

The secondary conversion unit may determine whether the coefficient v'[] (which sets the vector V) is arranged in the region R3 or the region R4 by the same method as the inverse secondary conversion unit 31121 described above.

In this way, the conversion coefficient included in the region including the lowest frequency component is determined by determining which region of the region R3 and the region R4 the secondary conversion and the inverse secondary conversion are applied according to the conditions. Can be preferably selected. As a result, the secondary conversion and the inverse secondary conversion can be applied more preferably.

(Application example 2 of inverse secondary conversion by inverse secondary conversion unit 31121)
Hereinafter, application example 2 of the inverse secondary conversion by the inverse secondary conversion unit 31121 will be described with reference to FIG. FIG. 14 is a diagram for explaining an example of the inverse secondary conversion by the inverse secondary conversion unit 31121 in the present embodiment.

The inverse secondary conversion unit 31121 has a first-class conversion basis T1 applied when the TU is less than 8 × 8 and a second-class conversion basis T2 applied when the TU is 8 × 8 or more. Perform the inverse secondary conversion using any of the above. Further, the inverse secondary conversion unit 31121 derives the conversion basis T1 of the first type from the conversion basis T2 of the second type.

For example, in the example shown in FIG. 14, the inverse secondary conversion unit 31121 is every four rows from the second type of conversion basis T2 represented by the 48 × 16 matrix, as shown in the example of RST8 × 8 in FIG. Extract four 4 × 16 matrices T1a, T1b, T1c and T1d. Subsequently, the inverse secondary conversion unit 31121 derives the first type of conversion basis T1 represented by the 16 × 16 matrix from these extracted matrices, as shown in the example of RST4 × 4 in FIG.

According to the above configuration, it suffices to have a table for holding a 48 × 16 matrix applied as RST 8 × 8, and a table for holding a 16 × 16 matrix applied as RST 4 × 4 is not required. Therefore, the memory of the table required for the inverse secondary conversion is about 6.1 Kbyte (48 × 16 × 8 = 6144 bytes), and the memory can be significantly reduced (here, about 25%). As a result, the inverse secondary conversion can be preferably applied.

Also in the secondary conversion unit, a 16 × 16 matrix applied as RST 4 × 4 can be derived from the 48 × 16 matrix applied as RST 8 × 8 by the same method as the inverse secondary conversion unit 31121 described above.

(Application example 3 of inverse secondary conversion by inverse secondary conversion unit 31121)
In the process of rearranging (converting) the vector (one-dimensional vector) V'of the one-dimensional array of each coefficient after the inverse secondary conversion into the vector (two-dimensional array) d [] of the two-dimensional array, the inverse secondary conversion unit 31121 , The method of rearranging (converting) is switched according to whether or not the pixels in a predetermined direction are referred to when making an intra prediction. Further, the predetermined direction described above includes the direction of the pixel referred to by the CCLM prediction.

As an example, the inverse secondary transformation unit 31121 puts the one-dimensional vector V'derived by the inverse secondary transformation into the region RU on the upper left side of the transformation residual shown in the example of the transformation residual after inverse quantization in FIG. Arrange them in a two-dimensional array d [].

First, the arrangement process by the above-mentioned inverse secondary conversion unit 31121 when a predetermined condition (If IntraPredMode is less than or equal to 34, or equal to INTRA_LT_CCLM, INTRA_L_CCLM) is satisfied will be described. In this case, the inverse secondary conversion unit 31121 arranges the one-dimensional vector V'in the two-dimensional array d [] [] according to the following equation.

Next, the placement process by the inverse secondary conversion unit 31121 when the predetermined condition is not satisfied (If IntraPredMode is more than 35, or equal to INTRA_T_CCLM) will be described. In this case, the inverse secondary conversion unit 31121 arranges the one-dimensional vector V'in the two-dimensional array d [] according to the following equation.

if (IntraPredMode <= 34 || IntraPredMode == INTRA_LT_CCLM || IntraPredMode == INTRA_L_CCLM)
d [x] [y] = v'[x + (y << log2 (RW))]
else // if (IntraPredMode> 34 || IntraPredMode == INTRA_T_CCLM)
d [x] [y] = v'[y + (x << log2 (RH))]
Here, RW and RH are widths and heights (eg, nStSize) in regions R2, R3, and R4. INTRA_LT_CCLM, INTRA_L_CCLM and INTRA_T_CCLM represent CCLM prediction modes. The CCLM prediction mode is a mode in which prediction parameters (scaling coefficient and offset) are derived by referring to the pixels on the left and above of the target block, a mode in which prediction parameters are derived by referring to the pixels on the left of the target block, and , This is a mode in which the prediction parameters are derived by referring to the pixels above the target block.

Therefore, when a predetermined condition is satisfied, the CCLM prediction mode is a prediction mode that refers to the pixels of the left block of the target block, and the one-dimensional vector V'is placed in the two-dimensional array d [] [] from left to right. , Place from top to bottom. Otherwise, CCLM prediction mode is a prediction mode that does not refer to the pixels in the left block of the target block, with the one-dimensional vector V'in the two-dimensional array d [] [] from top to bottom and from left to right. Deploy.

The inverse secondary conversion unit 31121 arranges the one-dimensional vector V'after the inverse secondary conversion into a two-dimensional array d [] [].
In the process of sorting to, the method of sorting (converting) is switched according to whether or not the pixels in a predetermined direction are referred to in the intra prediction. Further, the predetermined direction described above includes the direction of the pixel referred to by the CCLM prediction. Thereby, when the one-dimensional vector V'is rearranged in the two-dimensional array d [] [] and arranged in the above-mentioned region RU or the like, the one-dimensional vector V'can be arranged more preferably. As a result, the inverse secondary conversion can be applied more preferably.

(Scaling section 31122)
The scaling unit 31122 scales the coefficient (conversion coefficient) after conversion by the inverse secondary conversion unit 31121 by using the weight of the coefficient unit.

As a premise for explaining the details of scaling by the scaling unit 31122 in the present embodiment, first, the scaling normally applied will be described.

(Explanation of scaling)
Normal scaling, along with inverse quantization (at the same time), uses a quantization matrix to scale the transformation factors. However, since the quantization matrix corresponds to the core transformation factor, it is not appropriate to scale the secondary transformation factor.

(Explanation of scaling by scaling unit 31122)
The scaling unit 31122 in the present embodiment scales the coefficient after dequantization by the inverse secondary conversion unit 31121 (conversion coefficient). As a result, each value of the quantization matrix corresponds to the coefficient after the inverse secondary conversion, that is, the core conversion coefficient, so that it can be appropriately scaled. As a result, the inverse secondary conversion can be preferably applied.

The scaling unit 31122 may reduce the right shift amount when scaling. As a result, the accuracy of the calculation when scaling can be maintained.

(Structure with two scaling units)
The moving image decoding device that performs the inverse secondary conversion may include two scaling units, a scaling unit applied before the inverse secondary conversion unit 31121 and a scaling unit applied after the inverse secondary conversion unit 31121. The coefficient scaling unit 31122, which scales the converted coefficient by the inverse secondary conversion unit 31121, is described as the second scaling unit 31112 in the following configuration.

<Structure example 1 of inverse quantization / inverse conversion unit 311>
FIG. 20 is a block diagram showing the configuration of the inverse quantization / inverse conversion unit 311 of the present embodiment. The inverse quantization / inverse conversion unit 311 is composed of a first scaling unit 31111, an inverse secondary conversion unit 31121, a second scaling unit 31112 (scaling unit 31122), and an inverse core conversion unit 31123.

FIG. 21 is a flowchart showing a schematic process of the inverse quantization / inverse conversion unit 311 of the present embodiment.

S100: The first scaling unit 31111 performs the first scaling on the conversion coefficient. The first scaling unit 31111 includes a quantization parameter scale factor derivation described later.
S111: Determine whether the secondary conversion is valid.

S112: If secondary conversion is enabled, perform inverse secondary conversion.

S120: Performs a second scaling regardless of whether the secondary conversion is valid or not. The second scaling unit 31112 includes the quantization matrix scale factor derivation described later.
S130: Performs reverse core conversion.

When stIdx! = 0, the first scaling unit 31111 performs the first scaling on the conversion coefficient and transmits the conversion coefficient d [] [] to the inverse secondary conversion unit 31121. The inverse secondary conversion unit 31121 performs a second conversion (inverse secondary conversion) on the conversion coefficient, and outputs the converted conversion coefficient d [] [] to the second scaling unit 31112. The second scaling unit 31112 performs the second scaling on the input conversion coefficient d [] [] and transmits it to the inverse core conversion unit 31123. The inverse core conversion unit 31123 performs the first conversion (inverse core conversion) on the conversion coefficient after the second scaling, and obtains the conversion coefficient d [] [].

When stIdx == 0, the first scaling unit 31111 performs the first scaling on the conversion coefficient, and outputs the conversion coefficient d [] [] to the second scaling unit 31112. The second scaling unit 31112 performs the second scaling on the input conversion coefficient d [] [] and transmits it to the inverse core conversion unit 31123. The inverse core conversion unit 31123 performs the first conversion (inverse core conversion) on the conversion coefficient after the second scaling, and obtains the conversion coefficient d [] [].

FIG. 22 is a flowchart showing detailed processing of the inverse quantization / inverse conversion unit 311 of the present embodiment.

The first scaling unit 31111 performs the following scaling on the conversion coefficient decoded by the TU decoding unit according to the quantization coefficient qP and the size of the TU (nTbW, nTbH).

S101: Quantization parameter setting (not shown)
The first scaling unit 31111 sets the quantization parameter qP according to the color component cIdx.

qP = QP_Y (cIdx == 0)
qP = QP_Cb (cIdx == 1)
qP = QP_Cr (cIdx == 2)
S102: Derivation of the first shift value S102A: Derivation of the shift value depending on the TU size The first scaling unit 31111 derives the shift value depending on the TU size when the secondary conversion is on (stIdx! = 0).

bdShift = bitDepth + ((rectNonTsFlag? 8: 0) + (Log2 (nTbW) + Log2 (nTbH)) / 2) -5 + dep_quant_enabled_flag Expression (A-1A)
bdOffset = (1 << bdShift) >> 1
Note that bdShift is a shift value related to conversion, and is a value for matching energy changes before and after conversion according to the TU size and shape. Here, rectNorm is a correction term according to the TU shape. The first scaling unit 31111 is derived by the following equation.

rectNonTsFlag = ((((Log2 (nTbW) + Log2 (nTbH)) & 1) == 1 &&
transform_skip_flag [xTbY] [yTbY] == 0)
rectNorm = rectNonTsFlag? 181: 1
That is, if the shape of the TU is non-square ((Log2 (nTbW) + Log2 (nTbH)) & 1) and conversion skip is not used (transform_skip_flag [xTbY] [yTbY] == 0), rectNonTsFlag is set to 1. , Otherwise set to 0. Then, when the non-square flag rectNonTsFlag is 1, rectNorm is set to 181, and in other cases, 1 is set.

S102B: Derivation of core conversion shift value The first scaling unit 31111 derives a shift value for inverse core conversion when the secondary conversion is off (stIdx == 0).

bdShift = 0 equation (A-1B)
bdOffset = 0
Summarizing S102, the first scaling unit 31111 derives the shift values bdShift and bdOffset by the following equations according to whether or not the secondary conversion is valid (stIdx == 0).

If stIdx == 0, bdShift = 0, bdOffset = 0
If stIdx! = 0,
bdShift = bitDepth + ((rectNonTsFlag? 8: 0) + (Log2 (nTbW) + Log2 (nTbH)) / 2)
--5 + dep_quant_enabled_flag
bdOffset = (1 << bdShift) >> 1
When the secondary conversion is not valid (stIdx == 0), the first scaling unit 31111 performs the shift operation related to the conversion in the second scaling unit 31112. Therefore, here, the shift value related to the conversion to be applied after the multiplication of the scaling factor ls is applied. Set bdShift to 0. That is, after the scaling factor multiplication performed in the second scaling unit (after the quantization matrix processing), the shift processing related to the conversion is performed. When the secondary conversion is enabled (stIdx! = 0), it is necessary to complete the scaling process related to the conversion before the inverse secondary conversion process, so set the value for the shift process here.

S103: First scaling factor setting The first scaling unit 31111 derives the first intermediate scaling factor m.

When the secondary conversion is not valid (stIdx == 0), the scaling factor (intermediate scaling factor related to the quantization matrix) processing and the scaling processing related to the conversion are performed by the second scaling unit 31112, so m = 1.

S103C: Derivation of secondary conversion scale factor When secondary conversion is enabled (stIdx! = 0), a fixed value mLFNST (for example, 16) is set.

m = (stIdx == 0)? 1: mLFNST
mLFNST is a constant used for scaling the secondary transformation and may be 2,4,8,16,32,64 or the like.

S103D: Derivation of Quantization Parameter Scale Factor The first scaling unit 31111 derives the first scaling factor ls from the first intermediate scaling factor and the level Scale corresponding to the quantization parameter qP by the following equation. When dep_quant_enabled_flag is 1, it is derived by the following formula.

ls = (m * levelScale [(qP + 1)% 6]) << (qP / 6)
When dep_quant_enabled_flag == 0, it may be derived by the following formula.

ls = (m * levelScale [qP% 6]) << (qP / 6)
Where levelScale [] = {40, 45, 51, 57, 64, 72}.

The intermediate scaling factor m used in the first scaling unit of the present embodiment is a scalar value that does not depend on the position (x, y) of the conversion coefficient. Depending on the configuration, it may be processed as an array m [] [].

Since the first scaling factor is derived according to qP, it may be called the quantization parameter scale factor derivation.

S104: First scaling process The first scaling unit 31111 shifts the product of the decoded conversion coefficient TransCoeffLevel in the TU, the scaling factor ls, and the shape correction term rectNorm to the right by the shift value bsShift, thereby performing the first scaling (1st scaling). The first inverse quantization) is performed to derive dnc [] [].

dnc [x] [y] = (TransCoeffLevel [xTbY] [yTbY] [cIdx] [x] [y] * ls * rectNorm + bdOffset) >> bdShift
Finally, the first scaling unit 31111 may clip the inverse quantized conversion coefficient to derive d [x] [y].

d [x] [y] = Clip3 (CoeffMin, CoeffMax, dnc [x] [y])
The derived conversion coefficient is output to the second scaling unit 31112 or the inverse secondary conversion unit 31121.

S112: Inverse secondary conversion It is determined whether or not the secondary conversion is valid (S111), and if stIdx! = 0, the inverse secondary conversion is performed (S112).
The second scaling unit 31112 performs the following scaling on the conversion coefficient input from the first scaling unit 31111 or the inverse secondary conversion unit 31121 according to the quantization matrix ScalingFactor2 [] []. Hereinafter, ScalingFactor2 [] [] is an abbreviation for ScalingFactor2 [sizeIdW] [sizeIdH] [matridId] [] [].

S122: Second shift value setting S122C: Derivation of secondary conversion shift value The second scaling unit 31112 derives a shift value for secondary conversion when the secondary conversion is on (stIdx! = 0).

bdShift = Log2 (mLFNST) equation (A-2C)
S122A: TU size-dependent shift value derivation The second scaling unit 31112 derives the TU size-dependent shift value when the secondary conversion is off (stIdx == 0).

bdShift = bitDepth + ((rectNonTsFlag? 8: 0) + (Log2 (nTbW) + Log2 (nTbH)) / 2) -5 + dep_quant_enabled_flag Expression (A-2A)
bdOffset = (1 << bdShift) >> 1
This equation is equal to equation (A-1A).

Summarizing S122, the second scaling unit 31112 derives the bit shift bdShift and bdOffset by the following equations depending on whether or not the secondary conversion is valid (stIdx == 0).
If stIdx == 0,
bdShift = bitDepth + ((rectNonTsFlag? 8: 0) + (Log2 (nTbW) + Log2 (nTbH)) / 2)
--5 + dep_quant_enabled_flag
If stIdx! = 0,
bdShift = Log2 (mLFNST)
These are used to derive bdOffset.

bdOffset = (1 << bdShift) >> 1
Note that bdShift is a shift process related to conversion (shift process depending on the TU size) or a shift process for secondary conversion (mLFNST).

As shown above, the second scaling unit 31112 sets the value bdShift to the TU size in order to perform shift processing related to the conversion that was not performed by the first scaling unit 31111 when the secondary conversion is not enabled (stIdx == 0). Set according to. When the secondary conversion is enabled (stIdx! = 0), in the first scaling, the mLFNST multiplied as the intermediate scaling factor m is shifted to the right with the value Log2 (mLFNST) to restore it.

S123: Second scaling factor setting The second scaling unit 31112 derives a second intermediate scaling factor m [] [] according to the quantization matrix ScalingFactor2 [] []. In the following, scaling_list_enabled_flag is a flag indicating whether or not to use the quantization matrix.

S123A: Derivation of default scaling factor
If scaling_list_enabled_flag == 0, or transform_skip_flag == 1 and cIdx == 0, set the following as the second scaling factor.

m [x] [y] = 16 (x = 0..nTbW-1, y = 0..nTbH-1)
S123B: Derivation of quantization matrix scale factor Otherwise, the quantization matrix ScalingFactor2 [] [] is set as the second scaling factor.

m [x] [y] = ScalingFactor2 [sizeIdW] [sizeIdH] [matrixId] [x] [y]
sizeIdW = Log2 (nTbW)
sizeIdH = Log2 (nTbH)
Here, x = 0..nTbW-1, y = 0..nTbH-1, and matrixId is a variable derived from Max (sizeIdW, sizeIdH) and the prediction mode predMode.

S124: Second scaling process The second scaling unit 31112 adds the offset bdOffset to the product of the input conversion coefficient d [] [] and the second scaling factor m [] [], and right by the second shift value bsShift. By shifting, the second scaling (second inverse quantization) is performed, and dnc [] [] is derived.

dnc [x] [y] = (d [x] [y] * m [x] [y] + bdOffset) >> bdShift
Finally, the second scaling unit 31112 may clip the inverse quantized conversion coefficient to derive d [x] [y].

d [x] [y] = Clip3 (CoeffMin, CoeffMax, dnc [x] [y])
The derived conversion coefficient is output to the inverse core conversion unit 31123.

According to the above configuration, since the quantization matrix processing is performed after the inverse secondary conversion, an appropriate conversion coefficient weighting can be performed for each conversion coefficient position. In addition, it has the effect of performing inverse quantization before the inverse secondary transformation.

<Structure example 2 of inverse quantization / inverse conversion unit 311>
FIG. 23 is a block diagram showing the configuration of the inverse quantization / inverse conversion unit 311 having another configuration of the present embodiment. The inverse quantization / inverse conversion unit 311 is composed of a first scaling unit 31111, an inverse secondary conversion unit 31121, a second scaling unit 31112, and an inverse core conversion unit 31123.

24 and 25 are flowcharts showing the schematic processing of the inverse quantization / inverse conversion unit 311 of the present embodiment.

S200: The first scaling unit 31111 performs the first scaling on the conversion coefficient. The first scaling unit 31111 includes a quantization parameter scale factor derivation described later.
S211: Determine whether the secondary conversion is valid.

S212: If secondary conversion is enabled, reverse secondary conversion is performed.

S220: If secondary conversion is enabled, perform a second scaling. The second scaling unit 31112 includes the quantization matrix scale factor derivation described later.
S230: Performs reverse core conversion.

FIG. 25 is a diagram illustrating the second scaling S220. S220 consists of the following.

S221: Determine if the quantization matrix is valid.

S222: If the quantization matrix is valid, perform a second scaling.

When stIdx! = 0, the first scaling unit 31111 performs the first scaling on the conversion coefficient and transmits the conversion coefficient d [] [] to the inverse secondary conversion unit 31121. The inverse secondary conversion unit 31121 performs a second conversion (inverse secondary conversion) on the conversion coefficient, and outputs the conversion coefficient d [] [] to the second scaling unit 31112. The second scaling unit 31112 performs the second scaling on the input conversion coefficient d [] [] and transmits it to the inverse core conversion unit 31123. The inverse core conversion unit 31123 performs the first conversion (inverse core conversion) on the conversion coefficient after the second scaling, and obtains the conversion coefficient d [] [].

When stIdx == 0, the first scaling unit 31111 performs the first scaling on the conversion coefficient and transmits the conversion coefficient d [] [] to the inverse core conversion unit 31123. The inverse core conversion unit 31123 performs the first conversion (inverse core conversion) on the conversion coefficient after the first scaling, and obtains the conversion coefficient d [] [].

In this configuration, when stIdx == 0, the scaling process is completed only by the first scaling process before the inverse core conversion, and only when stIdx! = 0, the first scaling process and the inverse secondary before the inverse secondary conversion. The second scaling process after conversion is performed.

FIG. 26 is a flowchart showing detailed processing of the inverse quantization / inverse conversion unit 311 of the present embodiment.

The first scaling unit 31111 performs the following scaling on the conversion coefficient decoded by the TU decoding unit according to the quantization coefficient qP and the size of the TU (nTbW, nTbH).

S201: Quantization parameter setting (not shown)
The first scaling unit 31111 sets the quantization parameter qP according to the color component cIdx.

qP = QP_Y (cIdx == 0)
qP = QP_Cb (cIdx == 1)
qP = QP_Cr (cIdx == 2)
S202: Derivation of the first shift value S202A: Derivation of the shift value depending on the TU size The first scaling unit 31111 uses the TU size (nTbW, nTbH) to perform bit shift bdShift.
The bdOffset is derived by the following formula.

bdShift = bitDepth + ((rectNonTsFlag? 8: 0) + (Log2 (nTbW) + Log2 (nTbH)) / 2)
--5 + dep_quant_enabled_flag
bdOffset = (1 << bdShift) >> 1
Here, rectNorm is derived as follows.

rectNonTsFlag = ((((Log2 (nTbW) + Log2 (nTbH)) & 1) == 1 && transform_skip_flag [xTbY] [yTbY] == 0)
rectNorm = rectNonTsFlag? 181: 1
S203: First scaling factor setting The first scaling unit 31111 derives the first intermediate scaling factor m [] [].

S203C: Derivation of secondary conversion scale factor When the secondary conversion is valid and the scaling list is used (stIdx! = 0 && scaling_list_enabled_flag == 1), the first intermediate scaling factor m [x] [y] is set to a fixed value mLFNST (for example). Set to 16).

m [x] [y] = mLFNST
S203A: Derivation of default scale factor Other than that, if scaling_list_enabled_flag == 0 (does not use scaling list) or transform_skip_flag == 1 and cIdx == 0, m [x] [y] is set to 16.

m [x] [y] = 16 (x = 0..nTbW-1, y = 0..nTbH-1)
S203B: Quantization matrix scale factor derivation Otherwise, the intermediate scaling factor is set to the quantization matrix ScalingFactor2 [] [].

m [x] [y] = ScalingFactor2 [sizeIdW] [sizeIdH] [matrixId] [x] [y]
S203D: Derivation of quantization parameter scaling factor The first scaling unit 31111 derives the first scaling factor ls [] [] from the first intermediate scaling factor and the level Scale corresponding to the quantization parameter qP by the following equation. ..
When dep_quant_enabled_flag is 1, it is derived by the following formula.

ls [x] [y] = (m [x] [y] * levelScale [(qP + 1)% 6]) << (qP / 6)
When dep_quant_enabled_flag == 0, it may be derived by the following formula.

ls [x] [y] = (m [x] [y] * levelScale [qP% 6]) << (qP / 6)
Where levelScale [] = {40, 45, 51, 57, 64, 72}.

S204: 1st scaling process The 1st scaling unit 31111 shifts the product of the decoded conversion coefficient TransCoeffLevel in the TU, the scaling factor ls [] [], and the shape correction term rectNorm to the right by the shift value bsShift. Scaling of 1 (first inverse quantization) is performed to derive dnc [] [].

dnc [x] [y] = (TransCoeffLevel [xTbY] [yTbY] [cIdx] [x] [y] * ls [x] [y] * rectNorm + bdOffset) >> bdShift
Finally, the first scaling unit 31111 may clip the inverse quantized conversion coefficient to derive d [x] [y].

d [x] [y] = Clip3 (CoeffMin, CoeffMax, dnc [x] [y])
The derived conversion coefficient d [] [] is output to the inverse secondary conversion unit 31121 (when stIdx! = 0) or the inverse core conversion unit 31123 (when stIdx == 0). When stIdx == 0, the inverse quantization process using the scaling list (quantization matrix) is performed in the first scaling unit, and the conversion coefficient after scaling is output to the inverse core conversion unit 31123. When stIdx! = 0, scaling by the fixed value mLFNST related to the quantization parameter is performed in the first scaling unit, and inverse quantization using the scaling list is performed in the second scaling unit.

When performing inverse quantization using the scaling list (scaling_list_enabled_flag! = 0), the second scaling unit 31112 responds to the quantization matrix ScalingFactor2 [] [] with respect to the conversion coefficient input from the inverse secondary conversion unit 31121. And perform the following scaling.

S222: Second shift value setting S222C: Secondary conversion shift value derivation The second scaling unit 31112 derives the bit shift bdShift and bdOffset by the following equations.

bdShift = Log2 (mLFNST)
bdOffset = (1 << bdShift) >> 1
Note that bdShift is used for right shift to convert the conversion coefficient to an appropriate size after multiplying the scaling factor m [] [] described later. This is a process to restore the value multiplied by mLFSNT in the first scaling section.

S223: Second scaling factor setting S222C: Derivation of quantization matrix scale factor The second scaling unit 31112 derives a second intermediate scaling factor m [] [] according to the quantization matrix ScalingFactor2 [] [].

Set the quantization matrix ScalingFactor2 [] [] to the intermediate scaling factor.

m [x] [y] = ScalingFactor2 [sizeIdW] [sizeIdH] [matrixId] [x] [y]
sizeIdW = Log2 (nTbW)
sizeIdH = Log2 (nTbH)
Here, x = 0..nTbW-1, y = 0..nTbH-1, and matrixId is a variable derived from Max (sizeIdW, sizeIdH) and the prediction mode predMode.

S204: 2nd scaling process The 2nd scaling unit 31112 shifts the input conversion coefficient d [] [] and the 2nd scaling factor ls [] [] to the right by the 2nd shift value bsShift to make a second. Scaling (second inverse quantization) is performed to derive dnc [] [].

dnc [x] [y] = (d [x] [y] * m [x] [y] + bdOffset) >> bdShift
Finally, the second scaling unit 31112 may clip the inverse quantized conversion coefficient to derive d [x] [y].

d [x] [y] = Clip3 (CoeffMin, CoeffMax, dnc [x] [y])
The derived conversion coefficient is output to the inverse core conversion unit 31121.

According to the above configuration, since the quantization matrix processing is performed after the inverse secondary conversion, an appropriate conversion coefficient weighting can be performed for each conversion coefficient position. In addition, it has the effect of performing inverse quantization before the inverse secondary transformation.

According to the other configuration described above, when stIdx == 0, the process is completed only by the first scaling process, which has the effect of simplifying the process.

<Structure example 3 of inverse quantization / inverse conversion unit 311>
FIG. 27 is a block diagram showing the configuration of the inverse quantization / inverse conversion unit 311 having another configuration of the present embodiment. The inverse quantization / inverse conversion unit 311 is composed of a first scaling unit 31111, a third scaling unit 31113, an inverse secondary conversion unit 31121, a second scaling unit 31112, and an inverse core conversion unit 31123.

FIG. 28 is a flowchart showing a schematic process of the inverse quantization / inverse conversion unit 311 of the present embodiment.

S300ST: The inverse quantization / inverse conversion unit 311 determines whether or not the secondary conversion is valid (stIdx! = 0).

S300: When the secondary conversion is enabled (stIdx! = 0), the first scaling unit 31111 performs the first scaling on the conversion coefficient. The first scaling unit 31111 includes processing for deriving the secondary transformation scale factor and deriving the quantization parameter scale factor.
S300B: When the secondary conversion is not valid (stIdx == 0), the third scaling unit 31113 performs the third scaling on the conversion coefficient. The third scaling unit 31113 includes a default scale factor derivation, a quantization matrix scale factor derivation, and a quantization parameter scale factor derivation process.

S312: If secondary conversion is enabled, perform inverse secondary conversion.

S320: If the secondary transformation is valid (stIdx! = 0) and the quantization matrix is valid (scaling_list_enabled_flag == 1) is true, the second scaling is performed. The second scaling unit 31112 includes the process of deriving the quantization matrix scale factor described later.
S330: Performs reverse core conversion.

When stIdx! = 0 and the quantization matrix is valid, the first scaling unit 31111 performs the first scaling on the conversion coefficient and transmits the conversion coefficient d [] [] to the inverse secondary conversion unit 31121. The inverse secondary conversion unit 31121 performs a second conversion (inverse secondary conversion) on the conversion coefficient, and outputs the conversion coefficient d [] [] to the second scaling unit 31112. The second scaling unit 31112 performs the second scaling on the input conversion coefficient d [] [] and transmits it to the inverse core conversion unit 31123. The inverse core conversion unit 31123 performs the first conversion (inverse core conversion) on the conversion coefficient after the second scaling, and obtains the conversion coefficient d [] [].

When stIdx! = 0 and the quantization matrix is not valid, the first scaling unit 31111 performs the first scaling on the conversion coefficient and transmits the conversion coefficient d [] [] to the inverse secondary conversion unit 31121. The inverse secondary conversion unit 31121 performs a second conversion (inverse secondary conversion) on the conversion coefficient, and transmits the conversion coefficient d [] [] to the inverse core conversion unit 31123. The inverse core conversion unit 31123 performs the first conversion (inverse core conversion) to obtain the conversion coefficient d [] [].

When stIdx == 0, the third scaling unit 31113 performs the third scaling on the conversion coefficient and transmits the conversion coefficient d [] [] to the inverse core conversion unit 31123. The inverse core conversion unit 31123 performs the first conversion (inverse core conversion) on the conversion coefficient after the third scaling, and obtains the conversion coefficient d [] [].

In this configuration, if stIdx == 0 or the quantization matrix is not valid, the scaling process is completed only by the first or third scaling process before the inverse core conversion, and stIdx! = 0 and the quantization matrix is valid. Only in the case, the second scaling process after the inverse secondary conversion is performed.

FIG. 29 is a flowchart showing the detailed processing of the inverse quantization / inverse conversion unit 311 of the present embodiment.

When the secondary conversion is enabled (stIdx! = 0), the first scaling unit 31111 is as follows according to the quantization coefficient qP and the size of the TU (nTbW, nTbH) with respect to the conversion coefficient decoded by the TU decoding unit. Is scaled, and the converted conversion coefficient d [] [] after scaling is output to the inverse secondary conversion unit 31121.

S301: Quantization parameter setting (not shown)
The first scaling unit 31111 sets the quantization parameter qP according to the color component cIdx.

qP = QP_Y (cIdx == 0)
qP = QP_Cb (cIdx == 1)
qP = QP_Cr (cIdx == 2)
S302: Derivation of the first shift value S302A: Derivation of the TU size-dependent shift value The first scaling unit 31111 derives the bit shift bdShift and bdOffset by the following equations using the TU size (nTbW, nTbH).

bdShift = bitDepth + ((rectNonTsFlag? 8: 0) + (Log2 (nTbW) + Log2 (nTbH)) / 2)
--5 + dep_quant_enabled_flag
bdOffset = (1 << bdShift) >> 1
Here, rectNorm is derived as follows.

rectNonTsFlag = ((((Log2 (nTbW) + Log2 (nTbH)) & 1) == 1 && transform_skip_flag [xTbY] [yTbY] == 0)
rectNorm = rectNonTsFlag? 181: 1
S303: First scaling factor setting The first scaling unit 31111 derives the first intermediate scaling factor m [] [].

S303C: Derivation of secondary conversion scale factor When the secondary conversion is valid and the scaling list is used (stIdx! = 0 && scaling_list_enabled_flag == 1), the first intermediate scaling factor m [x] [y] is set to a fixed value mLFNST (for example). Set to 16).

m [x] [y] = mLFNST
S303D: Derivation of quantization parameter scaling factor The first scaling unit 31111 derives the first scaling factor ls [] [] from the first intermediate scaling factor and the level Scale corresponding to the quantization parameter qP by the following equation. ..
When dep_quant_enabled_flag is 1, it is derived by the following formula.

ls [x] [y] = (m [x] [y] * levelScale [(qP + 1)% 6]) << (qP / 6)
When dep_quant_enabled_flag == 0, it may be derived by the following formula.

ls [x] [y] = (m [x] [y] * levelScale [qP% 6]) << (qP / 6)
Where levelScale [] = {40, 45, 51, 57, 64, 72}.

S304: First scaling process The first scaling unit 31111 scales by shifting the product of the decoded conversion coefficient TransCoeffLevel in the TU, the scaling factor ls [] [], and the shape correction term rectNorm to the right by the shift value bsShift. (Inverse quantization) is performed to derive dnc [] [].

dnc [x] [y] = (TransCoeffLevel [xTbY] [yTbY] [cIdx] [x] [y] * ls [x] [y] * rectNorm + bdOffset) >> bdShift
Finally, the first scaling unit 31111 may clip the inverse quantized conversion coefficient to derive d [x] [y].

d [x] [y] = Clip3 (CoeffMin, CoeffMax, dnc [x] [y])
The derived conversion coefficient d [] [] is output to the inverse secondary conversion unit 31121. The inverse secondary conversion unit 31121 performs a second conversion (inverse secondary conversion) on the conversion coefficient, and outputs the conversion coefficient d [] [] to the second scaling unit 31112. The second scaling unit 31112 performs the second scaling on the input conversion coefficient d [] [] and transmits it to the inverse core conversion unit 31123. The processing of the second scaling S320 is the same as that of the second scaling S220 of FIG. 26, and the description thereof will be omitted.

When the secondary conversion is not valid (stIdx == 0), the third scaling unit 31113 is as follows according to the quantization coefficient qP and the size of the TU (nTbW, nTbH) with respect to the conversion coefficient decoded by the TU decoding unit. Scale. Regarding the process in which the same code as that of the first scaling unit 31111 is set, the same process as that of the first scaling unit 31111 is performed in the third scaling unit 31113, and thus the description thereof will be omitted.

S301: Quantization parameter setting S302: First shift value derivation S302A: TU size-dependent shift value derivation S303: First scaling factor setting The third scaling unit 31113 derives a third intermediate scaling factor m [] [].

S303A: Derivation of default scale factor When the scaling list is not used (scaling_list_enabled_flag == 0) or when transform_skip_flag == 1 and cIdx == 0, m [x] [y] is set to 16.

m [x] [y] = 16 (x = 0..nTbW-1, y = 0..nTbH-1)
S303B: Quantization matrix scale factor derivation Otherwise, m [x] [y] is set to the quantization matrix ScalingFactor2 [] [].

m [x] [y] = ScalingFactor2 [sizeIdW] [sizeIdH] [matrixId] [x] [y]
S303D: Derivation of quantization parameter scaling factor S304: First scaling process The derived conversion coefficient d [] [] is output to the inverse core conversion unit 31123.

According to the above configuration, since the quantization matrix processing is performed after the inverse secondary conversion, an appropriate conversion coefficient weighting can be performed for each conversion coefficient position. In addition, it has the effect of performing inverse quantization before the inverse secondary transformation.

According to the other configuration described above, when stIdx == 0, the process is completed only by the first scaling process, which has the effect of simplifying the process.

(Reverse core converter 31123)
The inverse core conversion unit 31123 applies the inverse core conversion to the coefficient (conversion coefficient) after conversion by the inverse secondary conversion unit 31121. In the inverse core conversion unit 31123, the conversion coefficient converted by the inverse secondary conversion unit 31121 may apply the inverse core conversion to the coefficient (conversion coefficient) after scaling by the scaling unit 31122. The inverse core conversion unit 31123 is a means for performing two one-dimensional conversions in the vertical direction and the horizontal direction, and is usually called a conversion unit. The inverse core conversion unit 31123 may be provided with a case where one or both of the vertical direction and the horizontal direction are skipped and only the magnitude conversion (scaling) of the conversion coefficient is performed.

The inverse core conversion unit 31123 converts the modified conversion coefficient d [] [] (for example, the conversion coefficient after the inverse secondary conversion) into the intermediate value e [] [] by the vertical one-dimensional conversion, and the intermediate value e [] [ ] To clip. The inverse core conversion unit 31123 converts the intermediate value g [] [] into the predicted residual r [] [], and the predicted residual r [] [] is sent to the adding unit 312.

More specifically, the inverse core conversion unit 31123 derives the first intermediate value e [x] [y] by the following equation.

e [x] [y] = Σ (transMatrix [y] [j] × d [x] [j]) (j = 0..nTbS -1)
Here, transMatrix [] [] (= transMatrixV [] []) is a conversion basis represented by a matrix of nTbS × nTbS derived using trTypeVer. nTbS is the height of TU nTbH. In the case of DCT2 4 × 4 conversion (nTbS = 4) with trType == 0, for example, transMatrix = {{29, 55, 74, 84} {74, 74, 0, -74} {84, -29, Use -74, 55} {55, -84, 74, -29}}. The symbol Σ means the process of adding the product of the matrix transMatrix [y] [j] and the conversion coefficient d [x] [j] for the subscript j up to j = 0 .. nTbS -1. That is, e [x] [y] is a vector x [j] consisting of d [x] [j] (j = 0 .. nTbS -1), which is each column of d [x] [y]. It is obtained by arranging the columns obtained from the product of (j = 0 .. nTbS-1) and the matrix elements transMatrix [y] [j].

The inverse core conversion unit 31123 clips the first intermediate value e [x] [y] and derives the second intermediate value g [x] [y] by the following equation.

g [x] [y] = Clip3 (coeffMin, coeffMax, (e [x] [y] + 64) >> 7)
The above equations 64 and 7 are numerical values determined by the bit depth of the conversion basis, and the above equation assumes that the conversion basis is 7 bits. Also, coeffMin and coeffMax are the minimum and maximum values of clipping.

The inverse core conversion unit 31123 is a conversion basis transMatrix [] [] (= transMatrixH [] []) represented by a matrix of nTbS × nTbS derived using trTypeHor. nTbS is the height of TU nTbH. The horizontal conversion unit 152123 predicts the intermediate value g [x] [y] by the horizontal one-dimensional conversion. Residual r [x] [
Convert to y].

r [x] [y] = Σ transMatrix [x] [j] × g [j] [y] (j = 0..nTbS -1)
The above symbol Σ means the process of adding the product of the matrices transMatrix [x] [j] and g [j] [y] for the subscript j up to j = 0 .. nTbS -1. That is, r [x] [y] is obtained from the product of g [j] [y] (j = 0 .. nTbS -1), which is each row of g [x] [y], and the matrix transMatrix. Obtained side by side.

The addition unit 312 adds the prediction image of the block input from the prediction image generation unit 308 and the prediction error input from the inverse quantization / inverse conversion unit 311 for each pixel to generate a decoded image of the block. The addition unit 312 stores the decoded image of the block in the reference picture memory 306, and outputs the decoded image to the loop filter 305.

[Modification example]
In the above example, when the TU is 8 × 8 or more, the secondary conversion unit applies the secondary conversion only to the NUMSTC conversion coefficients including the lowest frequency component among the conversion coefficients included in the TU, and the vector Derive F. Then, the inverse secondary conversion unit 31121 arranges the vector F'which has been quantized and inverse quantized on the vector F in the region including the lowest frequency component after the inverse secondary conversion. Further, the secondary conversion unit and the inverse secondary conversion unit 31121 are the first type conversion basis T1 applied when the TU is less than 8 × 8, and the first type applied when the TU is 8 × 8 or more. Secondary conversion and inverse secondary conversion are performed using one of the two conversion bases T2. Further, the secondary conversion unit and the inverse secondary conversion unit 31121 derive the conversion basis T1 of the first type from the conversion basis T2 of the second type.

However, in the present embodiment, the secondary conversion unit and the inverse secondary conversion unit 31121 may have the following functions instead of these functions. That is, when the TU is larger than 8 × 8, among the conversion coefficients included in the TU, the 8 × 8 region including the lowest frequency component is included in a part of the regions in which both the horizontal and vertical directions are high frequency components. The conversion coefficient to be obtained may be excluded from the targets of the secondary conversion and the inverse secondary conversion. Further, at least one of the region in which the 8 × 8 region including the low frequency component is extended in the horizontal direction and the region in which the 8 × 8 region including the lowest frequency component is extended in the vertical direction is subjected to the secondary conversion and the inverse secondary conversion. It may be included in the target. Examples of the size of the TU include sizes larger than 8x8 such as 16x16, 8x16 and 16x8.

(Application example 4 of inverse secondary conversion by inverse secondary conversion unit 31121)
Hereinafter, application example 4 of the inverse secondary conversion by the inverse secondary conversion unit 31121 will be described with reference to FIG. FIG. 15 is a diagram for explaining an example of a region to be subjected to the inverse secondary conversion in the modified example.

(Explanation of inverse secondary conversion)
In the inverse secondary transformation, when the TU is larger than 8 × 8, it is represented by a 64 × 16 matrix as RST 8 × 8 for the conversion coefficient of the 8 × 8 region RU on the upper left of the conversion residual after inverse quantization. A second type of transformation basis T2 may be applied. In this case, in the secondary conversion, the conversion coefficient included in the region excluding the region RU is zeroed out from the conversion residual after the inverse quantization shown in FIG. Here, the conversion coefficient included in the upper left 8 × 8 region RU in the conversion residual after inverse quantization is held. However, considering the distribution of conversion coefficients, it is not preferable to hold only the conversion coefficients included in the upper left 8 × 8 region RU and zero out the other regions.

(Explanation of inverse secondary conversion by inverse secondary conversion unit 31121)
On the other hand, in the present embodiment, as shown in the conversion coefficient selection example 4 of FIG. 15, the inverse secondary conversion unit 31121 has a part from the 8 × 8 region RU including the lowest frequency component to the part including the high frequency component. The conversion coefficient included in the region R5 may be excluded from the target of the inverse secondary conversion. Further, the inverse secondary conversion unit 31121 may include the region R6 in which the 8 × 8 region RU including the lowest frequency component is horizontally extended as the target of the inverse secondary conversion. In other words, when the inverse secondary conversion unit 31121 arranges the one-dimensional vector X'that has been subjected to the inverse secondary transformation to the one-dimensional vector F'after the inverse quantization in the 8 × 8 region RU including the lowest frequency component. , It is not necessary to arrange it in a part of the region R5 belonging to the high frequency component. Further, the inverse secondary conversion unit 31121 may store the one-dimensional vector X'in the region R6 in which the 8 × 8 region RU including the lowest frequency component is horizontally extended.

Further, as shown in the conversion coefficient selection example 5 of FIG. 15, the inverse secondary conversion unit 31121 includes the conversion coefficient included in a part of the region R7 including the high frequency component from the 8 × 8 region RU containing the lowest frequency component. May be excluded from the target of secondary conversion. Further, the inverse secondary conversion unit 31121 may include the region R8 in which the 8 × 8 region RU including the lowest frequency component is vertically expanded, as the target of the inverse secondary conversion. In other words, the inverse secondary converter 31121 arranges the one-dimensional vector V'in which the inverse-quantized one-dimensional vector F'is subjected to the inverse secondary transformation in the 8 × 8 region RU including the lowest frequency component of FIG. In this case, it is not necessary to arrange it in a part of the region R7 belonging to the high frequency component. Further, the inverse secondary conversion unit 31121 may store the one-dimensional vector V'in the region R8 in which the 8 × 8 region RU including the lowest frequency component is vertically extended.

Further, as shown in the conversion coefficient selection example 6 of FIG. 15, the inverse secondary conversion unit 31121 includes the conversion coefficient included in a part of the region R9 including the high frequency component from the 8 × 8 region RU containing the lowest frequency component. May be excluded from the target of secondary conversion. Further, the inverse secondary conversion unit 31121 extends the 8 × 8 region R including the lowest frequency component horizontally to the region R6 and the region R8 including the lowest frequency component 8 × 8 region R to the vertical direction. It may be included in the target of secondary conversion. In other words, the inverse secondary converter 31121 arranges the one-dimensional vector V'in which the inverse-quantized one-dimensional vector F'is subjected to the inverse secondary transformation in the 8 × 8 region RU including the lowest frequency component of FIG. In this case, it is not necessary to arrange it in a part of the region R9 belonging to the high frequency component. Further, the inverse secondary conversion unit 31121 includes 1 in a region R6 in which the 8 × 8 region RU including the lowest frequency component is horizontally extended and a region R8 in which the 8 × 8 region RU including the lowest frequency component is vertically extended. The dimension vector V'may be stored.

As described above, in the present embodiment, the inverse secondary conversion unit 31121 includes at least one of the region expanded in the horizontal direction and the region expanded in the vertical direction with respect to the region RU as the target of the inverse secondary conversion. As a result, the loss of information on the core conversion coefficient can be suppressed, and the inverse secondary conversion can be applied efficiently and preferably.

The inverse secondary conversion unit 31121 applies the inverse secondary conversion in the same manner as in the above example except for the position and number of the conversion coefficients to be selected.

Further, the secondary conversion unit may also apply the secondary conversion in the same manner as in the above example.

(Configuration of moving image encoding device)
Next, the configuration of the moving image coding device 11 according to the present embodiment will be described. FIG. 16 is a block diagram showing the configuration of the moving image coding device 11 according to the present embodiment. The moving image coding device 11 includes a prediction image generation unit 101, a subtraction unit 102, a conversion / quantization unit 103, an inverse quantization / inverse conversion unit 105, an addition unit 106, a loop filter 107, and a prediction parameter memory (prediction parameter storage unit). , Frame memory) 108, reference picture memory (reference image storage unit, frame memory) 109, coding parameter determination unit 110, parameter coding unit 111, and entropy coding unit 104.

The prediction image generation unit 101 generates a prediction image for each CU, which is a region in which each picture of the image T is divided. The prediction image generation unit 101 has the same operation as the prediction image generation unit 308 described above, and the description thereof will be omitted.

The subtraction unit 102 subtracts the pixel value of the predicted image of the block input from the prediction image generation unit 101 from the pixel value of the image T to generate a prediction error. The subtraction unit 102 outputs the prediction error to the conversion / quantization unit 103.

The conversion / quantization unit 103 calculates the conversion coefficient by frequency conversion for the prediction error input from the subtraction unit 102, and derives the quantization conversion coefficient by quantization. The conversion / quantization unit 103 outputs the quantization conversion coefficient to the entropy coding unit 104 and the inverse quantization / inverse conversion unit 105.

The conversion / quantization unit 103 includes a core conversion unit (first conversion unit, not shown), a second scaling unit (not shown), and a secondary conversion unit (second conversion unit, not shown). ing.

The core conversion unit applies the core conversion to the prediction error. The second scaling unit scales the conversion coefficient (core conversion coefficient) after conversion by the core conversion unit by the quantization matrix. The secondary conversion unit applies the secondary conversion to the core conversion coefficient after scaling. As a result, each weight of the quantization matrix corresponds to the core conversion coefficient value, so that it can be appropriately scaled. As a result, the secondary conversion can be preferably applied.

<Structure example 1 of conversion / quantization unit 103>
FIG. 30 is a flowchart showing a schematic process of the conversion / quantization unit 103 corresponding to the inverse quantization / inverse conversion unit 311 of the present embodiment described with reference to FIG.

S1100: The conversion / quantization unit 103 performs core conversion.

S1110: The conversion / quantization unit 103 performs the second forward scaling. The second forward scaling includes a scaling process using a quantization matrix.

S1121: Judge whether the secondary conversion is valid.

S1122: If secondary conversion is enabled, perform secondary conversion (forward secondary conversion).

S1130: The conversion / quantization unit 103 performs the first forward scaling. The first forward scaling includes a scaling process using the TU size.

Hereinafter, forward scaling refers to a process in which the conversion coefficient d [] [] is input and the conversion coefficient d [] [] is derived by the scaling process. The scaling process is a process of adding an offset to the product of the input signals to shift to the right, and a clip process may be performed in the middle of the process.

<Structure example 2 of conversion / quantization unit 103>
FIG. 31 is a flowchart showing a schematic process of the conversion / quantization unit 103 corresponding to the inverse quantization / inverse conversion unit 311 of the present embodiment described with reference to FIG. 23.

S1200: The conversion / quantization unit 103 performs core conversion.

S1211: The conversion / quantization unit 103 determines whether or not the secondary conversion is valid (stIdx! = 0).

S1212: When the secondary conversion is valid (stIdx! = 0), the second forward scaling is performed. The second forward scaling includes a scaling process using a quantization matrix.

S1222: Performs secondary conversion (forward secondary conversion).

S1230: The conversion / quantization unit 103 performs the first forward scaling. The first forward scaling includes a scaling process using the TU size.

<Structure example 3 of conversion / quantization unit 103>
FIG. 32 is a flowchart showing a schematic process of the conversion / quantization unit 103 corresponding to the inverse quantization / inverse conversion unit 311 of the present embodiment described with reference to FIG. 27.

S1300: The conversion / quantization unit 103 performs core conversion.

S1311: The conversion / quantization unit 103 determines whether the secondary conversion is valid (stIdx! = 0) and the quantization matrix is valid (scaling_list_enabled_flag == 1).

S1312: If the secondary transformation is valid (stIdx! = 0) and the quantization matrix is valid (scaling_list_enabled_flag == 1) is true, the second order scaling is performed. The second forward scaling includes a scaling process using a quantization matrix.

S1321: Judge whether the secondary conversion is valid.

S1322: If secondary conversion is enabled, perform secondary conversion (forward secondary conversion).

S1332: When the secondary conversion is valid (stIdx! = 0), the first forward scaling is performed. The first forward scaling includes a scaling process using the TU size.

S1332B: Otherwise, perform a third scaling. The third forward scaling includes a scaling process using the TU size.

In the (forward) secondary conversion applied in the moving image coding device 11, the processing S1-S4 of the inverse secondary conversion applied to the moving image decoding device 31 is applied in the reverse order of processing S1, S4, S3, S2. Performs almost the same processing.

In the process S1, the secondary conversion unit performs the same processing as the inverse secondary conversion unit 31121 except that the inputs and outputs of the secondary conversion have lengths nStOutSize and nonZeroSize, respectively.

In the process S4, the secondary conversion unit derives the coefficient v [] of the one-dimensional array of nStOutSize (or nStSize * nStSize) from the conversion coefficient d [] [] at a predetermined position in the TU.

In the process S3, the secondary conversion unit uses the coefficient v [] (vector V) of the one-dimensional array of nStOutSize and the conversion basis T [] [] by the following conversion to perform the one-dimensional coefficient u [] (vector F) of nonZeroSize. To get.

F = trans (T) × V
Here, trans (T) is the transpose matrix of T. The secondary conversion unit may derive the one-dimensional coefficient u [] (vector F) by the following equation.

F = Tinv × V
Here, Tinv is an inverse matrix of the conversion basis T composed of the first type of conversion basis T1 and the second type of conversion basis T2. Note that the secondary conversion unit may set trans (T) of the conversion basis T to Tinv by using an orthogonal matrix with respect to the conversion basis T.

In the actual processing, since T is a matrix of integer values, it is not T × Tinv = I (unit matrix) but a constant multiple of the unit matrix (T × Tinv = K2 × I, K2 is a constant). In this case, the secondary conversion unit uses a matrix that is a constant multiple of the inverse matrix as Tinv, but the transposed matrix may be used as it is.

In the process S2, the secondary conversion unit rearranges the one-dimensional coefficient u [] of nonZeroSize into a two-dimensional array to derive the conversion coefficient d [] [].

xC = (xSbIdx << log2StSize) + DiagScanOrder [log2StSize] [log2StSize] [x] [0]
yC = (ySbIdx << log2StSize) + DiagScanOrder [log2StSize] [log2StSize] [x] [1]
d [xC] [yC] = u [x]
Further, when the TU is 8 × 8 or more, the secondary conversion unit applies the secondary conversion only to the core conversion coefficients within NUMSTC including the lowest frequency component. The number of NUMSTCs may be 36 or less. For example, it may be 36 or 32. In addition, the secondary conversion unit is the first type of conversion basis T1 applied when the TU is less than 8 × 8, and the second type of conversion basis T2 applied when the TU is 8 × 8 or more. Perform a secondary conversion using either. Further, the secondary conversion unit derives the first type of conversion basis T1 from the second type of conversion basis T2. With any of these, the memory of the table required for the secondary conversion can be significantly reduced. As a result, the secondary conversion can be preferably applied.

Further, in the process of rearranging (converting) the two-dimensional array of each coefficient after the core conversion into the one-dimensional array, the secondary conversion unit determines whether or not to refer to the pixels in a predetermined direction at the time of intra prediction. , Switch the sorting (converting) method. In addition, the predetermined direction includes the direction of the pixel referred to by the CCLM prediction. As a result, when the two-dimensional array is rearranged into the one-dimensional vector V', the two-dimensional array can be rearranged more preferably into the one-dimensional vector V'. As a result, the secondary conversion can be applied more preferably.

The inverse quantization / inverse conversion unit 105 is the same as the inverse quantization / inverse conversion unit 311 (FIG. 15) in the moving image decoding device 31, and the description thereof will be omitted. The calculated prediction error is output to the addition unit 106.

A quantization conversion coefficient is input to the entropy coding unit 104 from the conversion / quantization unit 103, and a coding parameter is input from the parameter coding unit 111. The coding parameter is, for example, predMode.

The entropy coding unit 104 entropy-encodes the division information, the prediction parameters, the quantization conversion coefficient, and the like to generate a coded stream Te and outputs it.

The parameter coding unit 111 includes a header coding unit 1110 (not shown), a CT information coding unit 1111, a CU coding unit 1112 (prediction mode coding unit), an inter prediction parameter coding unit 112, and an intra prediction parameter coding unit 112. It has 113. The CU coding unit 1112 further includes a TU coding unit 1114.

The outline operation of each module will be described below. The parameter coding unit 111 performs parameter coding processing such as header information, division information, prediction information, and quantization conversion coefficient.

The CT information coding unit 1111 encodes QT, MT (BT, TT) division information and the like from the coded data.

The CU coding unit 1112 encodes CU information, prediction information, TU division flag, CU residual flag, and the like.

The TU coding unit 1114 encodes the QP update information (quantization correction value) and the quantization prediction error (residual_coding) when the TU includes a prediction error.

The CT information coding unit 1111 and the CU coding unit 1112 supply syntax elements such as inter prediction parameters, intra prediction parameters (intra_luma_mpm_flag, intra_luma_mpm_idx, intra_luma_mpm_remainder), and quantization conversion coefficients to the entropy coding unit 104.

(Structure of Intra Prediction Parameter Encoding Unit 113)
The intra prediction parameter coding unit 113 is the In input from the coding parameter determination unit 110.
From traPredMode, derive the format for encoding (for example, intra_luma_mpm_idx, intra_luma_mpm_remainder, etc.). The intra prediction parameter coding unit 113 includes a configuration that is partially the same as the configuration in which the intra prediction parameter decoding unit 304 derives the intra prediction parameter.

FIG. 17 is a schematic diagram showing the configuration of the intra-prediction parameter coding unit 113 of the parameter coding unit 111. The intra prediction parameter coding unit 113 includes a parameter coding control unit 1131, a luminance intra prediction parameter derivation unit 1132, and a color difference intra prediction parameter derivation unit 1133.

IntraPredModeY and IntraPredModeC are input to the parameter coding control unit 1131 from the coding parameter determination unit 110. The parameter coding control unit 1131 determines the intra_luma_mpm_flag by referring to the mpmCandList [] of the MPM candidate list derivation unit 30421. Then, intra_luma_mpm_flag and IntraPredModeY are output to the luminance intra prediction parameter derivation unit 1132. In addition, IntraPredModeC is output to the color difference intra prediction parameter derivation unit 1133.

The luminance intra prediction parameter derivation unit 1132 includes an MPM candidate list derivation unit 30421 (candidate list derivation unit), an MPM parameter derivation unit 11322, and a non-MPM parameter derivation unit 11323 (encoding unit, derivation unit). To.

The MPM candidate list derivation unit 30421 derives mpmCandList [] by referring to the intra prediction mode of the adjacent block stored in the prediction parameter memory 108. The MPM parameter derivation unit 11322 derives intra_luma_mpm_idx from IntraPredModeY and mpmCandList [] when intra_luma_mpm_flag is 1, and outputs it to the entropy coding unit 104. The non-MPM parameter derivation unit 11323 derives RemIntraPredMode from IntraPredModeY and mpmCandList [] when intra_luma_mpm_flag is 0, and outputs intra_luma_mpm_remainder to the entropy encoding unit 104.

The color difference intra prediction parameter derivation unit 1133 derives intra_chroma_pred_mode from IntraPredModeY and IntraPredModeC and outputs it.

The addition unit 106 generates a decoded image by adding the pixel value of the prediction image of the block input from the prediction image generation unit 101 and the prediction error input from the inverse quantization / inverse conversion unit 105 for each pixel. The addition unit 106 stores the generated decoded image in the reference picture memory 109.

The loop filter 107 applies a deblocking filter, SAO, and ALF to the decoded image generated by the addition unit 106. The loop filter 107 does not necessarily have to include the above three types of filters, and may have, for example, a configuration of only a deblocking filter.

The prediction parameter memory 108 stores the prediction parameters generated by the coding parameter determination unit 110 at positions predetermined for each target picture and CU.

The reference picture memory 109 stores the decoded image generated by the loop filter 107 at a predetermined position for each target picture and CU.

The coding parameter determination unit 110 selects one set from the plurality of sets of coding parameters. The coding parameter is the above-mentioned QT, BT or TT division information, prediction parameter, or a parameter to be coded generated in connection with these. The prediction image generation unit 101 generates a prediction image using these coding parameters.

The coding parameter determination unit 110 calculates an RD cost value indicating the magnitude of the amount of information and the coding error for each of the plurality of sets. The coding parameter determination unit 110 selects the set of coding parameters that minimizes the calculated cost value. As a result, the entropy coding unit 104 outputs the selected set of coding parameters as the coding stream Te. The coding parameter determination unit 110 stores the determined coding parameter in the prediction parameter memory 108.

[Modification example]
In the above example, when the TU is 8 × 8 or more, the secondary conversion unit applies the secondary conversion only to the core conversion coefficients within NUMSTC including the lowest frequency component. In addition, the secondary conversion unit is the first type of conversion basis T1 applied when the TU is less than 8 × 8, and the second type of conversion basis T2 applied when the TU is 8 × 8 or more. The secondary conversion is performed using any of the above. Further, the secondary conversion unit is configured to derive the first type of conversion basis T1 from the second type of conversion basis T2.

However, in the present embodiment, the secondary conversion unit may have the following functions instead of these functions. That is, when the TU has a size larger than 8 × 8, the secondary conversion unit has high frequencies in both the horizontal and vertical directions from the region of 8 × 8 including the lowest frequency component among the conversion coefficients included in the TU. The conversion coefficient included in a part of the region belonging to the component may be excluded from the target of the secondary conversion. Further, the secondary conversion unit includes at least one of a region in which the 8 × 8 region including the lowest frequency component is extended in the horizontal direction and a region in which the 8 × 8 region including the lowest frequency component is extended in the vertical direction. It may be included in the target of secondary conversion. As a result, information loss due to unencoded core conversion coefficients can be suppressed, and secondary conversion can be applied efficiently and preferably.

In addition, a part of the moving image coding device 11 and the moving image decoding device 31 in the above-described embodiment, for example, the entropy decoding unit 301, the parameter decoding unit 302, the loop filter 305, the prediction image generation unit 308, and the inverse quantization / reverse. Conversion unit 311, addition unit 312, prediction image generation unit 101, subtraction unit 102, conversion / quantization unit 103, entropy coding unit 104, inverse quantization / inverse conversion unit 105, loop filter 107, coding parameter determination unit 110 , The parameter coding unit 111 may be realized by a computer. In that case, the program for realizing this control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by the computer system and executed. The "computer system" referred to here is a computer system built in any of the moving image coding device 11 and the moving image decoding device 31, and includes hardware such as an OS and peripheral devices. Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, or a CD-ROM, or a storage device such as a hard disk built in a computer system. Furthermore, a "computer-readable recording medium" is a medium that dynamically holds a program for a short period of time, such as a communication line when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In that case, a program may be held for a certain period of time, such as a volatile memory inside a computer system serving as a server or a client. Further, the above-mentioned program may be a program for realizing a part of the above-mentioned functions, and may be a program for realizing the above-mentioned functions in combination with a program already recorded in the computer system.

Further, a part or all of the moving image coding device 11 and the moving image decoding device 31 in the above-described embodiment may be realized as an integrated circuit such as an LSI (Large Scale Integration). Each functional block of the moving image coding device 11 and the moving image decoding device 31 may be made into a processor individually, or a part or all of them may be integrated into a processor. Further, the method of making an integrated circuit is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. Further, when an integrated circuit technology that replaces an LSI appears due to advances in semiconductor technology, an integrated circuit based on this technology may be used.

Although one embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to the above, and various design changes and the like are made without departing from the gist of the present invention. It is possible to do.

[Application example]
The moving image coding device 11 and the moving image decoding device 31 described above can be mounted on and used in various devices for transmitting, receiving, recording, and reproducing moving images. The moving image may be a natural moving image captured by a camera or the like, or an artificial moving image (including CG and GUI) generated by a computer or the like.

First, it will be described with reference to FIG. 2 that the moving image coding device 11 and the moving image decoding device 31 described above can be used for transmitting and receiving moving images.

FIG. 2 shows a block diagram showing the configuration of the transmission device PROD_A equipped with the moving image coding device 11. As shown in the figure, the transmission device PROD_A has a coding unit PROD_A1 that obtains coded data by encoding a moving image, and a modulation signal by modulating a carrier with the coded data obtained by the coding unit PROD_A1. It includes a modulation unit PROD_A2 to obtain and a transmission unit PROD_A3 to transmit the modulation signal obtained by the modulation unit PROD_A2. The moving image coding device 11 described above is used as the coding unit PROD_A1.

The transmitter PROD_A has a camera PROD_A4 for capturing a moving image, a recording medium PROD_A5 for recording a moving image, an input terminal PROD_A6 for inputting a moving image from the outside, and a moving image as a source of the moving image to be input to the coding unit PROD_A1. , An image processing unit A7 for generating or processing an image may be further provided. In the figure, the configuration in which the transmitter PROD_A has all of these is illustrated, but some of them may be omitted.

The recording medium PROD_A5 may be a recording of an unencoded moving image, or a moving image encoded by a recording coding method different from the transmission coding method. It may be a thing. In the latter case, a decoding unit (not shown) that decodes the coded data read from the recording medium PROD_A5 according to the recording coding method may be interposed between the recording medium PROD_A5 and the coding unit PROD_A1.

Further, FIG. 2 shows a block diagram showing the configuration of the receiving device PROD_B equipped with the moving image decoding device 31. As shown in the figure, the receiving device PROD_B is obtained by a receiving unit PROD_B1 that receives a modulated signal, a demodulating unit PROD_B2 that obtains encoded data by demodulating the modulated signal received by the receiving unit PROD_B1, and a demodulating unit PROD_B2. It includes a decoding unit PROD_B3 that obtains a moving image by decoding the coded data. The moving image decoding device 31 described above is used as the decoding unit PROD_B3.

The receiving device PROD_B is a display PROD_B4 for displaying the moving image, a recording medium PROD_B5 for recording the moving image, and an output terminal for outputting the moving image to the outside as a supply destination of the moving image output by the decoding unit PROD_B3. It may also have PROD_B6. In the figure, the configuration in which the receiving device PROD_B is provided with all of these is illustrated, but some of them may be omitted.

The recording medium PROD_B5 may be used for recording an unencoded moving image, or may be encoded by a recording encoding method different from the transmission coding method. You may. In the latter case, a coding unit (not shown) that encodes the moving image acquired from the decoding unit PROD_B3 according to the recording coding method may be interposed between the decoding unit PROD_B3 and the recording medium PROD_B5.

The transmission medium for transmitting the modulated signal may be wireless or wired. Further, the transmission mode for transmitting the modulated signal may be broadcasting (here, a transmission mode in which the destination is not specified in advance) or communication (here, transmission in which the destination is specified in advance). Refers to an aspect). That is, the transmission of the modulated signal may be realized by any of wireless broadcasting, wired broadcasting, wireless communication, and wired communication.

For example, a broadcasting station (broadcasting equipment, etc.) / receiving station (television receiver, etc.) of terrestrial digital broadcasting is an example of a transmitting device PROD_A / receiving device PROD_B that transmits and receives modulated signals by radio broadcasting. Further, a broadcasting station (broadcasting equipment, etc.) / receiving station (television receiver, etc.) of cable television broadcasting is an example of a transmitting device PROD_A / receiving device PROD_B that transmits and receives modulated signals by wired broadcasting.

In addition, servers (workstations, etc.) / clients (television receivers, personal computers, smartphones, etc.) for VOD (Video On Demand) services and video sharing services using the Internet are transmitters that send and receive modulated signals via communication. This is an example of PROD_A / receiver PROD_B (usually, in LAN, either wireless or wired is used as a transmission medium, and in WAN, wired is used as a transmission medium). Here, personal computers include desktop PCs, laptop PCs, and tablet PCs. Smartphones also include multifunctional mobile phone terminals.

The client of the video sharing service has a function of decoding the encoded data downloaded from the server and displaying it on the display, as well as a function of encoding the moving image captured by the camera and uploading it to the server. That is, the client of the video sharing service functions as both the transmitting device PROD_A and the receiving device PROD_B.

Next, it will be described with reference to FIG. 3 that the moving image coding device 11 and the moving image decoding device 31 described above can be used for recording and reproducing a moving image.

FIG. 3 shows a block diagram showing the configuration of the recording device PROD_C equipped with the moving image coding device 11 described above. As shown in the figure, the recording device PROD_C has a coding unit PROD_C1 that obtains coded data by encoding a moving image and a writing unit PROD_C2 that writes the coded data obtained by the coding unit PROD_C1 to the recording medium PROD_M. And have. The moving image coding device 11 described above is used as the coding unit PROD_C1.

The recording medium PROD_M may be of a type built in the recording device PROD_C, such as (1) HDD (Hard Disk Drive) or SSD (Solid State Drive), or (2) SD memory. It may be a type that is connected to the recording device PROD_C, such as a card or USB (Universal Serial Bus) flash memory, or (3) DVD (Digital Versatile Disc: registered trademark) or BD (Blu-ray). It may be loaded in a drive device (not shown) built in the recording device PROD_C, such as Disc (registered trademark).

Further, the recording device PROD_C has a camera PROD_C3 that captures a moving image, an input terminal PROD_C4 for inputting a moving image from the outside, and a reception for receiving the moving image as a source of the moving image to be input to the coding unit PROD_C1. A unit PROD_C5 and an image processing unit PROD_C6 for generating or processing an image may be further provided. In the figure, the configuration provided by the recording device PROD_C is illustrated, but some of them may be omitted.

The receiving unit PROD_C5 may receive an unencoded moving image, or receives coded data encoded by a transmission coding method different from the recording coding method. It may be something to do. In the latter case, a transmission decoding unit (not shown) that decodes the coded data encoded by the transmission coding method may be interposed between the receiving unit PROD_C5 and the coding unit PROD_C1.

Examples of such a recording device PROD_C include a DVD recorder, a BD recorder, an HDD (Hard Disk Drive) recorder, and the like (in this case, the input terminal PROD_C4 or the receiving unit PROD_C5 is the main source of moving images). .. In addition, a camcorder (in this case, the camera PROD_C3 is the main source of moving images), a personal computer (in this case, the receiving unit PROD_C5 or the image processing unit C6 is the main source of moving images), and a smartphone (this In this case, the camera PROD_C3 or the receiving unit PROD_C5 is the main source of moving images), etc. are also examples of such a recording device PROD_C.

Further, FIG. 3 shows a block diagram showing the configuration of the reproduction device PROD_D equipped with the above-mentioned moving image decoding device 31. As shown in the figure, the playback device PROD_D includes a reading unit PROD_D1 that reads the coded data written in the recording medium PROD_M, and a decoding unit PROD_D2 that obtains a moving image by decoding the coded data read by the reading unit PROD_D1. , Is equipped. The moving image decoding device 31 described above is used as the decoding unit PROD_D2.

The recording medium PROD_M may be of a type built into the playback device PROD_D, such as (1) HDD or SSD, or (2) such as an SD memory card or USB flash memory. It may be of a type connected to the playback device PROD_D, or may be loaded into a drive device (not shown) built in the playback device PROD_D, such as (3) DVD or BD. Good.

Further, the playback device PROD_D has a display PROD_D3 for displaying the moving image, an output terminal PROD_D4 for outputting the moving image to the outside, and a transmitting unit for transmitting the moving image as a supply destination of the moving image output by the decoding unit PROD_D2. It may also have PROD_D5. In the figure, the configuration in which the playback device PROD_D is provided with all of these is illustrated, but some of them may be omitted.

The transmission unit PROD_D5 may transmit an unencoded moving image, or transmits coded data encoded by a transmission coding method different from the recording coding method. It may be something to do. In the latter case, it is preferable to interpose a coding unit (not shown) that encodes the moving image by a coding method for transmission between the decoding unit PROD_D2 and the transmitting unit PROD_D5.

Examples of such a playback device PROD_D include a DVD player, a BD player, an HDD player, and the like (in this case, the output terminal PROD_D4 to which a television receiver or the like is connected is the main supply destination of the moving image). .. In addition, a television receiver (in this case, display PROD_D3 is the main supply destination of moving images) and digital signage (also called electronic signage or electronic bulletin board, etc., and display PROD_D3 or transmitter PROD_D5 is the main supply destination of moving images. (First), desktop PC (in this case, output terminal PROD_D4 or transmitter PROD_D5 is the main supply destination of moving images), laptop or tablet PC (in this case, display PROD_D3 or transmitter PROD_D5 is video) An example of such a playback device PROD_D is a smartphone (in this case, the display PROD_D3 or the transmitter PROD_D5 is the main supply destination of the moving image), which is the main supply destination of the image.

(Hardware realization and software realization)
Further, each block of the moving image decoding device 31 and the moving image coding device 11 described above may be realized in hardware by a logic circuit formed on an integrated circuit (IC chip), or may be realized by hardware, or a CPU (Central Processing). It may be realized by software using Unit).

In the latter case, each of the above devices is a CPU that executes instructions of a program that realizes each function, a ROM (Read Only Memory) that stores the above program, and a RAM (Random) that expands the above program.
Access Memory), a storage device (recording medium) such as a memory for storing the above program and various data. Then, an object of the embodiment of the present invention is a record in which the program code (execution format program, intermediate code program, source program) of the control program of each of the above devices, which is software for realizing the above-mentioned functions, is recorded readable by a computer. It can also be achieved by supplying the medium to each of the above devices and having the computer (or CPU or MPU) read and execute the program code recorded on the recording medium.

Examples of the recording medium include tapes such as magnetic tapes and cassette tapes, magnetic disks such as floppy (registered trademark) disks / hard disks, and CD-ROMs (Compact Disc Read-Only Memory) / MO disks (Magneto-Optical discs). ) / MD (Mini Disc) / DVD (Digital Versatile Disc: registered trademark) / CD-R (CD Recordable) / Blu-ray Disc (registered trademark) and other disks including magneto-optical disks, IC cards (memory cards) (Including) / Cards such as optical cards, mask ROM / EPROM (Erasable Programmable Read-Only Memory) / EEPROM (Electrically Erasable and Programmable Read-Only Memory: registered trademark) / Semiconductor memories such as flash ROM, or PLD ( Logic circuits such as Programmable logic device) and FPGA (Field Programmable Gate Array) can be used.

Further, each of the above devices may be configured to be connectable to a communication network, and the above program code may be supplied via the communication network. This communication network is not particularly limited as long as it can transmit the program code. For example, Internet, Intranet, Extranet, LAN (Local Area Network), ISDN (Integrated Services Digital Network), VAN (Value-Added Network), CATV (Community Antenna television / Cable Television) communication network, Virtual Private network (Virtual Private) Network), telephone line network, mobile communication network, satellite communication network, etc. can be used. Further, the transmission medium constituting this communication network may be any medium as long as it can transmit the program code, and is not limited to a specific configuration or type. For example, even wired such as IEEE (Institute of Electrical and Electronic Engineers) 1394, USB, power line carrier, cable TV line, telephone line, ADSL (Asymmetric Digital Subscriber Line) line, infrared data such as IrDA (Infrared Data Association) and remote control , BlueTooth (registered trademark), IEEE802.11 wireless, HDR (High Data Rate), NFC (Near Field Communication), DLNA (Digital Living Network Alliance: registered trademark), mobile phone network, satellite line, terrestrial digital broadcasting network, etc. It is also available wirelessly. The embodiment of the present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

The embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims. That is, an embodiment obtained by combining technical means appropriately modified within the scope of the claims is also included in the technical scope of the present invention.

The embodiment of the present invention is suitably applied to a moving image decoding device that decodes coded data in which image data is encoded, and a moving image coding device that generates coded data in which image data is encoded. be able to. Further, it can be suitably applied to the data structure of the coded data generated by the moving image coding device and referenced by the moving image decoding device.

31 Video decoding device
301 Entropy Decryptor
302 Parameter decoder
3020 Header decoder
308 Prediction image generator
311 Inverse quantization / inverse conversion
312 Addition part
11 Video coding device
101 Predictive image generator
102 Subtraction section
103 Conversion / Quantization Department
104 Entropy encoding section
105 Inverse quantization / inverse conversion
107 Loop filter
110 Coded parameter determination unit
111 Parameter encoding section
1110 Header encoding
1111 CT information coding unit
1112 CU encoding unit (prediction mode encoding unit)
1114 TU coder
3111 Inverse quantization unit
3112 Inverse converter
31121 Inverse secondary converter
31122 Scaling section
31123 Reverse core converter
31111 1st scaling section
31113 3rd scaling section
31112 2nd scaling section

Claims (6)

An image decoding device that reversely converts the conversion coefficient for each conversion unit.
A first scaling unit that scales with respect to the decoded conversion coefficient,
A second conversion unit that applies an inverse secondary conversion to the conversion coefficient,
A second scaling unit that scales with respect to the conversion coefficient after conversion by the second conversion unit, and
An image decoding apparatus including a first conversion unit that applies an inverse core conversion to a conversion coefficient after scaling by the first scaling unit or the second scaling unit. The first scaling unit described above derives a shift value that uses the size of the conversion unit or a shift value of a predetermined value that does not use the size of the variable unit.
Derivation of scale factors using quantization parameters
First scaling is performed on the conversion coefficient using the shift value and the scale factor.
When the quantization matrix is effective, the second scaling unit derives a scale factor using the quantization matrix, and uses the scale factor to perform the second scaling on the conversion coefficient. The image decoding apparatus according to claim 1. The first scaling unit described above derives a shift value that uses the size of the conversion unit when the secondary conversion is valid, and a shift value of a predetermined value that does not use the size of the conversion unit in other cases. Derivation of scale factors using quantization parameters
First scaling is performed on the conversion coefficient using the shift value and the scale factor.
The second scaling unit derives a shift value of a predetermined value that does not use the size of the conversion unit when the secondary conversion is effective, and a shift value that uses the size of the conversion unit in other cases.
When the quantization matrix is valid, the scale factor using the quantization matrix is derived, and in other cases, the scale factor of a predetermined value is derived.
The image decoding apparatus according to claim 2, wherein a second scaling is performed on a conversion coefficient using the scale factor. The first scaling unit described above derives a shift value using the size of the conversion unit.
Derivation of scale factors using quantization parameters
When the secondary transformation is not valid and the quantization matrix is valid, the scale factor using the quantization matrix is derived.
First scaling is performed on the conversion coefficient using the shift value and the scale factor.
When the secondary conversion is effective and the quantization matrix is effective, the second scaling unit derives a scale factor using the quantization matrix, and uses the scale factor to obtain a second scale factor with respect to the conversion coefficient. The image decoding apparatus according to claim 1, wherein the scaling of 2 is performed. The first scaling unit described above derives a shift value using the size of the conversion unit, derives a scale factor of a predetermined value when the secondary conversion is valid and the quantization matrix is valid, and derives the quantization parameter. Derived the scale factor using
When the secondary transformation is not valid and the quantization matrix is valid, the scale factor using the quantization matrix is derived.
First scaling is performed on the conversion coefficient using the shift value and the scale factor.
When the secondary conversion is effective and the quantization matrix is effective, the second scaling unit derives a scale factor using the quantization matrix, and uses the scale factor to obtain a second scale factor with respect to the conversion coefficient. The image decoding apparatus according to claim 1, wherein the scaling of 2 is performed. It is an image coding device that derives the conversion coefficient by converting each coefficient after conversion of the prediction error for each conversion unit.
A first conversion unit that applies core conversion to the prediction error, and
A second scaling unit that scales with respect to the coefficient after conversion by the first conversion unit,
A second conversion unit that applies a secondary conversion to the conversion coefficient after scaling by the scaling unit, and
An image coding device including a first scaling unit that scales with respect to a coefficient after conversion by the second conversion unit.

Images