JPWO2018061563A1 - Affine motion vector deriving device, predictive image generating device, moving image decoding device, and moving image encoding device - Google Patents

Abstract

An affine motion vector deriving device is realized which can appropriately switch whether to apply 4-parameter affine processing or 6-parameter affine processing. The AMVP prediction parameter derivation unit (3032) and the affine prediction unit (30372) are control points set in the reference block that shares the vertex with the target block with the motion vector of each of the plurality of sub-blocks that make up the target block. The calculation is performed with reference to the motion vector in step (4), and whether to perform 4-parameter affine processing or 6-parameter affine processing is switched according to at least one of the shape and the size of the target block.

Description

  Embodiments of the present invention relate to an affine motion vector derivation device, a predicted image generation device, a moving image decoding device, and a moving image coding device.

  A moving picture coding apparatus that generates coded data by coding a moving picture to efficiently transmit or record a moving picture, and a moving picture that generates a decoded picture by decoding the coded data. An image decoding device is used.

  As a specific moving picture coding method, for example, a method proposed in H.264 / AVC or High-Efficiency Video Coding (HEVC) may be mentioned.

  In such a moving picture coding method, an image (picture) constituting a moving picture is a slice obtained by dividing the image, a coding unit obtained by dividing the slice (coding unit (coding unit (Coding Unit)). (Also referred to as CU) and a hierarchical structure including a prediction unit (PU) which is a block obtained by dividing a coding unit and a transform unit (TU), and coding / It is decoded.

  Also, in such a moving picture coding method, a predicted picture is usually generated based on a locally decoded picture obtained by coding / decoding an input picture, and the predicted picture is generated from the input picture (original picture). The prediction residual obtained by subtraction (sometimes referred to as "difference image" or "residual image") is encoded. As a method of generating a prediction image, inter-screen prediction (inter prediction) and intra-screen prediction (intra prediction) can be mentioned.

  Moreover, the affine prediction of Non-Patent Document 1 can be mentioned as a technology of moving picture coding and decoding in recent years.

"Algorithm Description of Joint Exploration Test Model 3", JVET-C1002, Joint Video Exploration Team (JVET) of ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11, 2016-05-31 published Improved affine motion prediction, JVET-C0062, Joint Video Exploration Team (JVET) of ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11, 2016-05-17 published

  In the affine prediction of Non-Patent Document 1, the motion vector of each of a plurality of sub-blocks included in the target block is referred to the motion vector of two control points based on the affine prediction with four degrees of freedom (four-parameter affine) Calculate. In the affine prediction of Non-Patent Document 2, motion vectors of subblocks are calculated with reference to motion vectors of three control points based on affine prediction (six-parameter affine) having six degrees of freedom.

  Although the processing of the six-parameter affine contributes to the improvement of the coding efficiency as a whole as compared to the processing of the four-parameter affine, the movement of control points necessary for processing the affine when looking at individual blocks There is a problem that the code amount in vector coding increases. In addition, since the motion vector accuracy of the control point is easily influenced by the motion vector accuracy, and the motion vector accuracy of the control point is low and the deviation from the true motion vector is large, the motion vector calculated by applying the six parameter affine process. The first problem is that the accuracy of the problem is further reduced.

  Also, in the 4-parameter affine processing, two control points set in the reference block are used. There is a second problem that the processing accuracy of the four-parameter affine decreases if two appropriate points are not used as control points.

  In order to solve the first problem described above, in the affine motion vector deriving device that derives the motion vector of each of the subblocks that configure the target PU, the affine motion vector deriving device includes a plurality of subblocks included in the target block. The motion vector of each block is calculated with reference to the motion vector at a control point set in a reference block sharing a vertex with the target block, and at least one of the shape and the size of the target block Accordingly, it is switched whether to calculate the motion vectors of two control points to perform 4-parameter affine processing or calculate the motion vectors of three control points to perform 6-parameter affine processing.

  Further, in order to solve the first problem described above, a predicted image generation device according to an aspect of the present invention is an affine image generation device for generating a predicted image used for encoding or decoding of a moving image. A motion vector deriving unit and a predicted image generating unit are provided, and the affine motion vector deriving unit is configured to set each motion vector of the plurality of sub-blocks included in the target block into a reference block sharing a vertex with the target block. It calculates with reference to the motion vector at the set control point, calculates the motion vector of the two control points according to at least one of the shape and the size of the target block, and processes the 4-parameter affine. Switching between calculation of motion vectors of three control points and processing of six parameters affine, and the predicted image generation unit Generating a predicted image by referring to the motion vector of the serial control points.

  Further, in order to solve the first problem described above, a predicted image generation device according to an aspect of the present invention is an affine image generation device for generating a predicted image used for encoding or decoding of a moving image. A motion vector deriving unit and a predicted image generating unit are provided, and the affine motion vector deriving unit is configured to set each motion vector of the plurality of sub-blocks included in the target block into a reference block sharing a vertex with the target block. It is calculated by referring to the motion vector at the set control point, and according to at least one of the shape and the size of the reference block, the motion vector of two control points is calculated to process the four parameter affine. Switching between calculation of motion vectors of three control points and processing of six parameters affine, and the predicted image generation unit Generating a predicted image by referring to the motion vector of the serial control points.

  Further, in order to solve the second problem described above, a predicted image generation device according to an aspect of the present invention is an affine image generation device for generating a predicted image used for encoding or decoding of a moving image. A motion vector deriving unit and a predicted image generating unit are provided, and the affine motion vector deriving unit is configured to set each motion vector of the plurality of sub-blocks included in the target block into a reference block sharing a vertex with the target block. The control point is calculated with reference to the motion vector at the set control point, and the control point used in the processing of the four parameter affine is changed according to the shape of the target block or the shape of the reference block. The image generation unit generates a predicted image by referring to the motion vector of the control point.

  According to the embodiment of the present invention, in order to calculate the motion vector of each of the plurality of sub-blocks included in the target block with high accuracy, whether four-parameter affine processing is applied or six-parameter affine processing is applied Can be switched appropriately. In addition, it is possible to reduce the amount of code in the coding of the motion vector of the control point, which is necessary when performing affine processing.

  Also, according to embodiments of the present invention, appropriate control points can be used in the processing of a four parameter affine.

It is a figure which shows the hierarchical structure of the data of the coding stream which concerns on this embodiment. It is a figure which shows the pattern of PU split mode. (A) to (h) show the partition shapes when the PU division mode is 2Nx2N, 2NxN, 2NxnU, 2NxnD, Nx2N, nLx2N, nRx2N, and NxN, respectively. It is a conceptual diagram which shows an example of a reference picture and a reference picture list. It is a block diagram which shows the structure of the image coding apparatus which concerns on this embodiment. It is the schematic which shows the structure of the image decoding apparatus which concerns on this embodiment. It is the schematic which shows the structure of the inter estimated image generation part of the image coding apparatus which concerns on this embodiment. It is the schematic which shows the structure of the merge prediction parameter derivation | leading-out part which concerns on this embodiment. It is the schematic which shows the structure of the AMVP prediction parameter derivation | leading-out part which concerns on this embodiment. It is a flowchart which shows operation | movement of the motion vector decoding process of the image decoding apparatus which concerns on this embodiment. It is the schematic which shows the structure of the inter prediction parameter encoding part of the image coding apparatus which concerns on this embodiment. It is the schematic which shows the structure of the inter estimated image generation part which concerns on this embodiment. It is the schematic which shows the structure of the inter prediction parameter decoding part which concerns on this embodiment. It is a figure which shows the example which derives motion vector spMvLX [xi] [yj] of each subblock which comprises PU (horizontal width nPbW) which is object which predicts a motion vector. (A) is a figure for demonstrating bilateral matching (Bilateral matching). (B) is a figure for demonstrating template matching (Template matching). FIG. 7 is a diagram showing an example of the position of a prediction unit used to derive control point motion vectors in AMVP mode and merge mode. It is a figure which shows the example of the square sub-block whose one side is BW in which the control point V0 of the object block (horizontal width W, height H) which is the object which predicts a motion vector is located in the upper left vertex. It is a flowchart which shows an example of a process in which the inter prediction parameter decoding part determines the number of control points which derive | lead-out motion vector based on the shape of object PU. It is a flowchart which shows another example of a process which the number of control points which an inter prediction parameter decoding part derives | leads-out motion vector based on the shape of object PU. It is a flowchart which shows another example of a process which an inter prediction parameter decoding part determines the number of control points which derive | lead-out motion vector based on the shape of object PU. It is a flowchart which shows an example of a process in which the inter prediction parameter decoding part determines the number of control points which derive | lead-out a motion vector based on the size of object PU. It is a flowchart which shows another example of a process in which the inter prediction parameter decoding part determines the number of control points which derive | lead-out a motion vector based on the size of object PU. It is a table | surface which shows the process for every size at the time of using log2 (puWidth) + log2 (puHeight) as a value which shows the size of object PU. It is a table | surface which shows the process for every size at the time of using min (puWidth, puHeight) as a value which shows the size of object PU. It is a flowchart which shows an example of a process which the number of control points which an inter prediction parameter decoding part derives | requires a motion vector based on both the shape and size of object PU. It is a flowchart which shows another example of a process which the number of control points which an inter prediction parameter decoding part derives | leads-out a motion vector based on both the shape and size of object PU. It is a table showing an example of processing of an affine prediction part for every size and shape of object PU. It is a table showing another example of processing of the affine prediction unit for each size and shape of the target PU. It is a flowchart which shows an example of a process which the inter prediction parameter decoding part determines which process of 4 parameter affine and 6 parameter affine to perform based on the shape of an adjacent block. It is a figure for demonstrating the example of selection of the number of control points by the process shown in FIG. It is a flowchart which shows an example of a process which the inter prediction parameter decoding part determines which process of 4 parameter affine and 6 parameter affine to perform based on the size of an adjacent block. It is a figure for demonstrating the example of selection of the number of control points by the process shown in FIG. It is a flowchart of a process which an inter prediction parameter decoding part determines the position of the control point which derives a motion vector based on the shape of object PU. It is a figure which shows the example of the position of the control point which the inter prediction parameter decoding part of 3rd Embodiment determines. It is a flowchart of a process which the inter prediction parameter decoding part determines the position of the point of the adjacent block used for derivation | leading-out of the motion vector of a control point based on the shape of an adjacent block. It is a figure which shows the example of the position of the control point which the inter prediction parameter decoding part of 4th Embodiment determines. It is a flowchart of a process which an inter prediction parameter decoding part determines the position of the control point which derives a motion vector based on the shape of an adjacent block. It is a figure which shows the example of the position of the control point which the inter prediction parameter decoding part 303 of 5th Embodiment determines. It is the figure shown about the composition of the transmitting device carrying the picture coding device concerning this embodiment, and the receiving device carrying a picture decoding device. (A) shows a transmitting apparatus equipped with an image coding apparatus, and (b) shows a receiving apparatus equipped with an image decoding apparatus. It is the figure shown about the recording device carrying the picture coding device concerning this embodiment, and the composition of the reproduction device carrying a picture decoding device. (A) shows a recording apparatus equipped with an image coding apparatus, and (b) shows a reproduction apparatus equipped with an image decoding apparatus. It is a schematic diagram showing composition of an image transmission system concerning this embodiment.

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

  FIG. 40 is a schematic view showing the configuration of the image transmission system 1 according to the present embodiment.

  The image transmission system 1 is a system that transmits a code obtained by coding an image to be coded, decodes the transmitted code, and displays the image. The image transmission system 1 is configured to include an image encoding device (moving image encoding device) 11, a network 21, an image decoding device (moving image decoding device) 31, and an image display device 41.

  An image T representing an image of a single layer or a plurality of layers is input to the image coding device 11. A layer is a concept used to distinguish a plurality of pictures when there is one or more pictures that constitute a certain time. For example, if the same picture is encoded by a plurality of layers having different image quality and resolution, it becomes scalable coding, and if a picture of different viewpoints is encoded by a plurality of layers, it becomes view scalable coding. When prediction (inter-layer prediction, inter-view prediction) is performed between pictures of a plurality of layers, coding efficiency is greatly improved. Also, even in the case where prediction is not performed (simulcast), encoded data can be summarized.

  The network 21 transmits the encoded stream Te generated by the image encoding device 11 to the image decoding device 31. The network 21 is the Internet, a wide area network (WAN), a small area network (LAN), or a combination of these. The network 21 is not necessarily limited to a two-way communication network, and may be a one-way communication network for transmitting broadcast waves such as terrestrial digital broadcasting and satellite broadcasting. In addition, the network 21 may be replaced by a storage medium recording a coded stream Te such as a DVD (Digital Versatile Disc) or a BD (Blue-ray Disc).

  The image decoding apparatus 31 decodes each of the encoded streams Te transmitted by the network 21 and generates one or more decoded images Td which are respectively decoded.

  The image display device 41 displays all or a part of one or more decoded images Td generated by the image decoding device 31. The image display device 41 includes, for example, a display device such as a liquid crystal display or an organic EL (Electro-luminescence) display. In spatial scalable coding and SNR scalable coding, when the image decoding device 31 and the image display device 41 have high processing capabilities, they display enhancement layer images with high image quality and have only lower processing capabilities. , The base layer image which does not require the processing capability and the display capability as high as the enhancement layer.

<Operator>
The operators used herein are described below.

  >> is a right bit shift, << is a left bit shift, & is a bitwise AND, | is a bitwise OR, and | = is a sum operation (OR) with another condition.

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

  Clip3 (a, b, c) is a function that clips c to a value between a and b, and returns a if c <a, b if c> b, otherwise Is a function that returns c (where a <= b).

<Structure of Coded Stream Te>
Prior to detailed description of the image encoding device 11 and the image decoding device 31 according to the present embodiment, the data structure of the encoded stream Te generated by the image encoding device 11 and decoded by the image decoding device 31 will be described. .

  FIG. 1 is a diagram showing a hierarchical structure of data in a coded stream Te. The coded stream Te illustratively includes a sequence and a plurality of pictures forming the sequence. (A) to (f) in FIG. 1 respectively represent a coded video sequence defining the sequence SEQ, a coded picture defining the picture PICT, a coding slice defining the slice S, and a coding slice defining slice data. It is a figure which shows a coding tree unit contained in data, coding slice data, and a coding unit (Coding Unit; CU) contained in a coding tree unit.

(Encoded video sequence)
In the encoded video sequence, a set of data to which the image decoding device 31 refers in order to decode the sequence SEQ to be processed is defined. As shown in FIG. 1A, 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 an addition. It includes supplemental information SEI (Supplemental Enhancement Information). Here, the value shown after # indicates a layer ID. Although FIG. 1 shows an example in which coded data of # 0 and # 1, that is, layer 0 and layer 1 exist, the type of layer and the number of layers do not depend on this.

  A video parameter set VPS is a set of coding parameters common to a plurality of moving pictures and a set of coding parameters related to the plurality of layers included in the moving picture and each layer in a moving picture composed of a plurality of layers. A set is defined.

  In the sequence parameter set SPS, a set of coding parameters to be referred to by the image decoding device 31 for decoding the target sequence is defined. For example, the width and height of the picture are defined. In addition, multiple SPS may exist. In that case, one of a plurality of SPSs is selected from PPS.

  In the picture parameter set PPS, a set of coding parameters to which the image decoding device 31 refers to to decode each picture in the target sequence is defined. For example, a reference value of quantization width (pic_init_qp_minus 26) used for decoding a picture and a flag (weighted_pred_flag) indicating application of weighted prediction are included. In addition, multiple PPS may exist. In that case, one of a plurality of PPSs is selected from each picture in the target sequence.

(Coded picture)
In the coded picture, a set of data to which the image decoding device 31 refers in order to decode the picture PICT to be processed is defined. The picture PICT includes slices S0 to SNS _-1 (NS is the total number of slices included in the picture PICT), as shown in (b) of FIG.

In the following, when there is no need to distinguish between slices S0 to SNS _-1 , suffixes of reference numerals may be omitted and described. Further, the same is true for other data that is included in the encoded stream Te described below and that is suffixed.

(Coding slice)
In the coding slice, a set of data to which the image decoding device 31 refers in order to decode the slice S to be processed is defined. The slice S includes a slice header SH and slice data SDATA as shown in (c) of FIG.

  The slice header SH includes a coding parameter group to which the image decoding device 31 refers in order to determine the decoding method of the target slice. The slice type specification information (slice_type) for specifying a slice type is an example of a coding parameter included in the slice header SH.

  As slice types that can be designated by slice type designation information, (1) I slice using only intra prediction at the time of encoding, (2) P slice using unidirectional prediction at the time of encoding or intra prediction, (3) B-slice using uni-directional prediction, bi-directional prediction, or intra prediction at the time of encoding.

  Note that the slice header SH may include a reference (pic_parameter_set_id) to the picture parameter set PPS included in the encoded video sequence.

(Encoding slice data)
In the encoded slice data, a set of data to which the image decoding device 31 refers in order to decode the slice data SDATA to be processed is defined. The slice data SDATA includes a coding tree unit (CTU: Coding Tree Unit) as shown in (d) of FIG. The CTU is a block of a fixed size (for example, 64 × 64) that configures a slice, and may also be referred to as a largest coding unit (LCU: Largest Coding Unit).

(Encoding tree unit)
As shown in (e) of FIG. 1, a set of data to which the image decoding device 31 refers in order to decode a coding tree unit to be processed is defined. The coding tree unit is divided by recursive quadtree division. A tree-structured node obtained by recursive quadtree division is called a coding node (CN). The intermediate nodes of the quadtree are coding nodes, and the coding tree unit itself is also defined as the top coding node. The CTU includes a split flag (cu_split_flag), and when cu_split_flag is 1, the CTU is split into four coding nodes CN. When cu_split_flag is 0, the coding node CN is not split, and has one coding unit (CU: Coding Unit) as a node. The coding unit CU is an end node of the coding node and is not further divided. The coding unit CU is a basic unit of coding processing.

  When the size of the coding tree unit CTU is 64x64 pixels, the size of the coding unit can be 64x64 pixels, 32x32 pixels, 16x16 pixels, or 8x8 pixels.

(Coding unit)
As shown in (f) of FIG. 1, a set of data to which the image decoding device 31 refers in order to decode a coding unit to be processed is defined. Specifically, the coding unit is composed of a prediction tree, a transformation tree, and a CU header CUH. In the CU header, a prediction mode, a division method (PU division mode), and the like are defined.

  In the prediction tree, prediction information (reference picture index, motion vector, etc.) of each prediction unit (PU) obtained by dividing the coding unit into one or more is defined. Stated differently, a prediction unit is one or more non-overlapping regions that make up a coding unit. Also, the prediction tree includes one or more prediction units obtained by the above-mentioned division. In addition, below, the prediction unit which divided | segmented the prediction unit further is called a "subblock." The sub block is composed of a plurality of pixels. If the size of the prediction unit and the subblock is equal, there is one subblock in the prediction unit. If the prediction unit is larger than the size of the subblock, the prediction unit is divided into subblocks. For example, when the prediction unit is 8x8 and the subblock is 4x4, the prediction unit is divided into four subblocks, which are horizontally divided into two and vertically divided into two.

  The prediction process may be performed for each prediction unit (sub block).

  Broadly speaking, there are two types of division in the prediction tree: intra prediction and inter prediction. Intra prediction is prediction in the same picture, and inter prediction refers to prediction processing performed between mutually different pictures (for example, between display times, between layer images).

  In the case of intra prediction, there are 2Nx2N (the same size as the coding unit) and NxN as a division method.

  Also, in the case of inter prediction, the division method is encoded according to PU division mode (part_mode) of encoded data, 2Nx2N (the same size as the encoding unit), 2NxN, 2NxnU, 2NxnD, Nx2N, nLx2N, nRx2N, and There are NxN etc. Note that 2NxN and Nx2N indicate 1: 1 symmetric division, and 2NxnU, 2NxnD and nLx2N and nRx2N indicate 1: 3 and 3: 1 asymmetric division. The PUs included in the CU are expressed as PU0, PU1, PU2, PU3 in order.

  (A) to (h) of FIG. 2 specifically illustrate the shapes of partitions (positions of boundaries of PU division) in respective PU division modes. (A) of FIG. 2 shows a 2Nx2N partition, and (b), (c) and (d) show 2NxN, 2NxnU, and 2NxnD partitions (horizontally long partitions), respectively. (E), (f) and (g) show partitions (vertical partitions) in the case of Nx2N, nLx2N and nRx2N, respectively, and (h) shows a partition of NxN. Note that the horizontally long partition and the vertically long partition are collectively referred to as a rectangular partition, and 2Nx2N and NxN are collectively referred to as a square partition.

  Also, in the transform tree, the coding unit is divided into one or more transform units, and the position and size of each transform unit are defined. In other words, a transform unit is one or more non-overlapping regions that make up a coding unit. Also, the transformation tree includes one or more transformation units obtained by the above-mentioned division.

  Partitions in the transform tree may be allocated as a transform unit a region of the same size as the encoding unit, or may be based on recursive quadtree partitioning as in the case of CU partitioning described above.

  A conversion process is performed for each conversion unit.

(Prediction parameter)
The prediction image of a prediction unit (PU: Prediction Unit) is derived by prediction parameters associated with PU. The prediction parameters include intra prediction prediction parameters or inter prediction prediction parameters. Hereinafter, prediction parameters for inter prediction (inter prediction parameters) will be described. The inter prediction parameter includes prediction list use flags predFlagL0 and predFlagL1, reference picture indexes refIdxL0 and refIdxL1, and motion vectors mvL0 and mvL1. The prediction list use flags predFlagL0 and predFlagL1 are flags indicating whether a reference picture list called an L0 list or an L1 list is used, respectively, and a reference picture list corresponding to a value of 1 is used. In the present specification, when "a flag indicating whether or not it is XX", if the flag is other than 0 (for example, 1) is XX, it is assumed that 0 is not XX; Treat 1 as true, 0 as false, and so on. However, in an actual apparatus or method, other values may be used as true values or false values.

  Syntax elements for deriving inter prediction parameters included in encoded data include, for example, PU split mode part_mode, merge flag merge_flag, merge index merge_idx, inter prediction identifier inter_pred_idc, reference picture index refIdxLX, predicted vector index mvp_LX_idx, There is a difference vector mvdLX, a PU affine application flag pu_affine_enable_flag, and a PU affine mode flag pu_affine_mode_flag.

(Reference picture list)
The reference picture list is a list of reference pictures stored in the reference picture memory 306. FIG. 3 is a conceptual diagram showing an example of a reference picture and a reference picture list. In FIG. 3A, the rectangle is a picture, the arrow is a reference of the picture, the horizontal axis is time, and I, P and B in the rectangle are intra pictures, uni-predicted pictures, bi-predicted pictures, and numbers in the rectangle are decoded. Show the order. As shown in the figure, the decoding order of pictures is I0, P1, B2, B3, B4, and the display order is I0, B3, B2, B4, B1, P1. FIG. 3B shows an example of the reference picture list. The reference picture list is a list representing reference picture candidates, and one picture (slice) may have one or more reference picture lists. In the example of the figure, the target picture B3 has two reference picture lists, an L0 list RefPicList0 and an L1 list RefPicList1. Reference pictures when the target picture is B3 are I0, P1, and B2, and the reference pictures have these pictures as elements. In each prediction unit, which picture in the reference picture list RefPicListX is actually referred to is designated by the reference picture index refIdxLX. The figure shows an example in which reference pictures P1 and B2 are referenced by refIdxL0 and refIdxL1.

(Merge forecast and AMVP forecast)
The prediction parameter decoding (encoding) method includes a merge prediction (merge) mode and an AMVP (Adaptive Motion Vector Prediction) mode. The merge flag merge_flag is a flag for identifying these. The merge prediction mode is a mode used to be derived from the prediction parameter of the already processed neighboring PU without including the prediction list use flag predFlagLX (or inter prediction identifier inter_pred_idc), the reference picture index refIdxLX, and the motion vector mvLX in the encoded data. The AMVP mode is a mode in which the inter prediction identifier inter_pred_idc, the reference picture index refIdxLX, and the motion vector mvLX are included in the encoded data. The motion vector mvLX is encoded as a prediction vector index mvp_LX_idx that identifies the prediction vector mvpLX and a difference vector mvdLX.

  The inter prediction identifier inter_pred_idc is a value indicating the type and the number of reference pictures, and takes any one of PRED_L0, PRED_L1, and PRED_BI. PRED_L0 and PRED_L1 indicate that reference pictures managed by reference pictures in the L0 list and the L1 list are used, respectively, and indicate that one reference picture is used (uniprediction). PRED_BI indicates using two reference pictures (bi-prediction BiPred), and uses reference pictures managed by the L0 list and the L1 list. The predicted vector index mvp_LX_idx is an index indicating a predicted vector, and the reference picture index refIdxLX is an index indicating a reference picture managed in the reference picture list. LX is a description method used when L0 prediction and L1 prediction are not distinguished, and parameters for L0 list and parameters for L1 list are distinguished by replacing LX with L0 and L1.

  The merge index merge_idx is an index indicating whether, of prediction parameter candidates (merge candidates) derived from the PU for which processing has been completed, any prediction parameter is used as a prediction parameter of a target PU (target block) to be decoded.

(Motion vector)
The motion vector mvLX indicates the amount of deviation between blocks on two different pictures. The prediction vector and the difference vector relating to the motion vector mvLX are referred to as a prediction vector mvpLX and a difference vector mvdLX, respectively.

(Inter prediction identifier inter_pred_idc and prediction list usage flag predFlagLX)
The relationship between the inter prediction identifier inter_pred_idc, and the prediction list use flag predFlagL0, predFlagL1 is as follows, and can be mutually converted.

inter_pred_idc = (predFlagL1 << 1) + predFlagL0
predFlagL0 = inter_pred_idc & 1
predFlagL1 = inter_pred_idc >> 1
The inter prediction parameter may use a prediction list use flag or may use an inter prediction identifier. Further, the determination using the prediction list use flag may be replaced with the determination using the inter prediction identifier. Conversely, the determination using the inter prediction identifier may be replaced with the determination using the prediction list utilization flag.

(Judgment of bi-prediction biPred)
The flag biPred of bi-prediction BiPred can be derived depending on whether both of the two prediction list use flags are 1. For example, it can be derived by the following equation.

biPred = (predFlagL0 == 1 && predFlagL1 == 1)
The flag biPred can also be derived based on whether or not the inter prediction identifier is a value indicating that two prediction lists (reference pictures) are used. For example, it can be derived by the following equation.

biPred = (inter_pred_idc == PRED_BI)? 1: 0
The above equation can also be expressed by the following equation.

biPred = (inter_pred_idc == PRED_BI)
For example, a value of 3 can be used as PRED_BI.

(PU affine application flag, PU affine mode flag)
The PU affine application flag pu_affine_enable_flag is a flag indicating whether to apply affine prediction. The PU affine mode flag pu_affine_mode_flag (also simply referred to as affine mode) is a flag indicating whether to apply a four-parameter affine or a six-parameter affine.

(Configuration of image decoding apparatus)
Next, the configuration of the image decoding device 31 (moving image decoding device) according to the present embodiment will be described. FIG. 5 is a schematic view showing the configuration of the image decoding device 31 according to the present embodiment. The image decoding device 31 includes an entropy decoding unit 301, a prediction parameter decoding unit (prediction image decoding device) 302, a loop filter 305, a reference picture memory 306, a prediction parameter memory 307, a prediction image generation unit (prediction image generation device) 308, and an inverse A quantization / inverse DCT unit 311 and an addition unit 312 are included.

  Further, the prediction parameter decoding unit 302 is configured to include an inter prediction parameter decoding unit 303 and an intra prediction parameter decoding unit 304. The prediction image generation unit 308 includes an inter prediction image generation unit 309 (prediction image generation unit) and an intra prediction image generation unit 310.

  The entropy decoding unit 301 performs entropy decoding on the encoded stream Te input from the outside to separate and decode individual codes (syntax elements). The separated codes include prediction information for generating a prediction image and residual information for generating a difference image.

  The entropy decoding unit 301 outputs a part of the separated code to the prediction parameter decoding unit 302. The part of the separated code is, for example, prediction mode predMode, PU division mode part_mode, merge flag merge_flag, merge index merge_idx, inter prediction identifier inter_pred_idc, reference picture index refIdxLX, prediction vector index mvp_LX_idx, difference vector mvdLX. Control of which code to decode is performed based on an instruction of the prediction parameter decoding unit 302. The entropy decoding unit 301 outputs the quantization coefficient to the inverse quantization / inverse DCT unit 311. The quantization coefficient is a coefficient obtained by performing DCT (Discrete Cosine Transform, discrete cosine transformation) on the residual signal in the encoding process and quantizing the coefficient.

  The inter prediction parameter decoding unit 303 decodes the inter prediction parameter 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 inter prediction parameter decoding unit 303 outputs the decoded inter prediction parameter to the prediction image generation unit 308, and stores the inter prediction parameter in the prediction parameter memory 307. Details of the inter prediction parameter decoding unit 303 will be described later.

  The intra prediction parameter decoding unit 304 decodes the intra prediction parameter 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 is a parameter used in a process of predicting a CU in one picture, for example, an intra prediction mode IntraPredMode. 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 different intra prediction modes for luminance and chrominance. In this case, the intra prediction parameter decoding unit 304 decodes a luminance prediction mode IntraPredModeY as a luminance prediction parameter and a chrominance prediction mode IntraPredModeC as a chrominance prediction parameter. The luminance prediction mode IntraPredModeY is a 35 mode, and planar prediction (0), DC prediction (1), and direction prediction (2 to 34) correspond to each other. The color difference prediction mode IntraPredModeC uses one of planar prediction (0), DC prediction (1), direction prediction (2 to 34), and LM mode (35). The intra prediction parameter decoding unit 304 decodes a flag indicating whether IntraPredModeC is the same mode as the luminance mode, and if it indicates that the flag is the same mode as the luminance mode, IntraPredModeY is assigned to IntraPredModeC, and the flag indicates the luminance If it indicates that the mode is different from the mode, planar prediction (0), DC prediction (1), direction prediction (2 to 34), and LM mode (35) may be decoded as IntraPredModeC.

  The loop filter 305 applies a filter such as a deblocking filter, a sample adaptive offset (SAO), or an adaptive loop filter (ALF) to the decoded image of the CU generated by the adding unit 312.

  The reference picture memory 306 stores the decoded image of the CU generated by the adding unit 312 in a predetermined position for each picture and CU to be decoded.

  The prediction parameter memory 307 stores prediction parameters in a predetermined position for each picture to be decoded and each prediction unit (or sub block, fixed size block, pixel). Specifically, the prediction parameter memory 307 stores the inter prediction parameter decoded by the inter prediction parameter decoding unit 303, the intra prediction parameter decoded by the intra prediction parameter decoding unit 304, and the prediction mode predMode separated by the entropy decoding unit 301. . The inter prediction parameters to be stored include, for example, a prediction list use flag predFlagLX (inter prediction identifier inter_pred_idc), a reference picture index refIdxLX, and a motion vector mvLX.

  The prediction image generation unit 308 receives the prediction mode predMode input from the entropy decoding unit 301, and also receives a prediction parameter from the prediction parameter decoding unit 302. Further, the predicted image generation unit 308 reads the reference picture from the reference picture memory 306. The prediction image generation unit 308 generates a PU prediction image using the input prediction parameters and the read reference picture in the prediction mode indicated by the prediction mode predMode.

  Here, when the prediction mode predMode indicates the inter prediction mode, the inter prediction image generation unit 309 uses the inter prediction parameter input from the inter prediction parameter decoding unit 303 and the read reference picture to interpolate the predicted image of the PU by inter prediction. Generate

  The inter-predicted image generation unit 309 sets the motion vector mvLX based on the target PU from the reference picture indicated by the reference picture index refIdxLX with respect to the reference picture list (L0 list or L1 list) in which the prediction list use flag predFlagLX is 1. Is read out from the reference picture memory 306. The inter-prediction image generation unit 309 performs prediction based on the read reference picture block to generate a PU prediction image. The inter prediction image generation unit 309 outputs the generated prediction image of PU to the addition unit 312.

  When the prediction mode predMode indicates the intra prediction mode, the intra prediction image generation unit 310 performs intra prediction using the intra prediction parameter input from the intra prediction parameter decoding unit 304 and the read reference picture. Specifically, the intra predicted image generation unit 310 reads, from the reference picture memory 306, neighboring PUs which are pictures to be decoded and which are in a predetermined range from the target PU among PUs that have already been decoded. The predetermined range is, for example, one of the left, upper left, upper, and upper right adjacent PUs when the target PU moves sequentially in the order of so-called raster scan, and varies depending on the intra prediction mode. The order of raster scan is an order of sequentially moving from the left end to the right end for each row from the top to the bottom in each picture.

  The intra predicted image generation unit 310 performs prediction on the read adjacent PU in the prediction mode indicated by the intra prediction mode IntraPredMode to generate a predicted image of PU. The intra predicted image generation unit 310 outputs the generated predicted image of PU to the addition unit 312.

  When the intra prediction parameter decoding unit 304 derives an intra prediction mode different in luminance and color difference, the intra prediction image generation unit 310 determines planar prediction (0), DC prediction (1), direction according to the luminance prediction mode IntraPredMode Y. The prediction image of PU of luminance is generated by any of prediction (2 to 34), and planar prediction (0), DC prediction (1), direction prediction (2 to 34), LM mode according to the color difference prediction mode IntraPredModeC The prediction image of color difference PU is generated by any of (35).

  The inverse quantization / inverse DCT unit 311 inversely quantizes the quantization coefficient input from the entropy decoding unit 301 to obtain a DCT coefficient. The inverse quantization / inverse DCT unit 311 performs inverse DCT (Inverse Discrete Cosine Transform) on the obtained DCT coefficient to calculate a residual signal. The inverse quantization / inverse DCT unit 311 outputs the calculated residual signal to the addition unit 312.

  The addition unit 312 adds, for each pixel, the predicted image of the PU input from the inter predicted image generation unit 309 or the intra predicted image generation unit 310 and the residual signal input from the inverse quantization / inverse DCT unit 311, Generate a PU decoded image. The addition unit 312 stores the generated PU decoded image in the reference picture memory 306, and externally outputs a decoded image Td in which the generated PU decoded image is integrated for each picture.

(Configuration of inter prediction parameter decoding unit)
Next, the configuration of the inter prediction parameter decoding unit 303 will be described.

  FIG. 12 is a schematic diagram showing a configuration of the inter prediction parameter decoding unit 303 according to the present embodiment. The inter prediction parameter decoding unit 303 includes an inter prediction parameter decoding control unit 3031, an AMVP prediction parameter derivation unit 3032 (affine motion vector derivation unit, affine motion vector derivation device), an addition unit 3035, a merge prediction parameter derivation unit 3036, and subblock prediction The configuration includes a parameter derivation unit 3037.

  The inter prediction parameter decoding control unit 3031 instructs the entropy decoding unit 301 to decode a code (syntax element) related to inter prediction, and a code (syntax element) included in the encoded data, for example, PU division mode part_mode , Merge flag merge_flag, merge index merge_idx, inter prediction identifier inter_pred_idc, reference picture index refIdxLX, prediction vector index mvp_LX_idx, difference vector mvdLX is extracted.

  The inter prediction parameter decoding control unit 3031 first extracts the merge flag merge_flag. When the inter prediction parameter decoding control unit 3031 expresses that a syntax element is to be extracted, it instructs the entropy decoding unit 301 to decode a syntax element, which means that the corresponding syntax element is read out from the encoded data. Do.

  If the merge flag merge_flag is 0, that is, indicates the AMVP prediction mode, the inter prediction parameter decoding control unit 3031 extracts an AMVP prediction parameter from the encoded data using the entropy decoding unit 301. As the AMVP prediction parameters, for example, there are inter prediction identifier inter_pred_idc, reference picture index refIdxLX, prediction vector index mvp_LX_idx, difference vector mvdLX. The AMVP prediction parameter derivation unit 3032 derives a prediction vector mvpLX from the prediction vector index mvp_LX_idx. Details will be described later. The inter prediction parameter decoding control unit 3031 outputs the difference vector mvdLX to the addition unit 3035. The adding unit 3035 adds the prediction vector mvpLX and the difference vector mvdLX to derive a motion vector.

  When the merge flag merge_flag indicates 1, that is, indicates a merge prediction mode, the inter prediction parameter decoding control unit 3031 extracts a merge index merge_idx as a prediction parameter related to merge prediction. The inter prediction parameter decoding control unit 3031 outputs the extracted merge index merge_idx to the merge prediction parameter derivation unit 3036 (details will be described later), and outputs the sub block prediction mode flag subPbMotionFlag to the sub block prediction parameter derivation unit 3037. The sub-block prediction parameter derivation unit 3037 divides the PU into a plurality of sub-blocks according to the value of the sub-block prediction mode flag subPbMotionFlag, and derives a motion vector in units of sub-blocks. That is, in the sub-block prediction mode, a prediction block is predicted in small blocks of 4x4 or 8x8. In a method of dividing a CU into a plurality of partitions (PUs such as 2NxN, Nx2N, NxN, etc.) and encoding syntax of prediction parameters in units of partitions in the image coding device 11 described later, sub block prediction mode In the above, a plurality of sub-blocks are grouped into a set, and the syntax of the prediction parameter is encoded for each set, so that motion information of many sub-blocks can be encoded with a small code amount.

  More specifically, the sub-block prediction parameter derivation unit 3037 performs sub-block prediction in the sub-block prediction mode. The space-time sub-block prediction unit 30371, affine prediction unit 30372 (affine motion vector derivation unit, affine motion vector derivation device , And a matching prediction unit 30373.

(Sub block prediction mode flag)
Here, a method of deriving the sub-block prediction mode flag subPbMotionFlag indicating whether the prediction mode of a certain PU is the sub-block prediction mode in the image decoding device 31 and the image encoding device 11 (details will be described later) will be described. . The image decoding device 31 and the image encoding device 11 derive the sub-block prediction mode flag subPbMotionFlag based on which one of a spatial sub-block prediction SSUB, a temporal sub-block prediction TSUB, an affine prediction AFFINE, and a matching prediction MAT is used. Do. For example, when the prediction mode selected by a certain PU is N (for example, N is a label indicating a selected merge candidate), the sub-block prediction mode flag subPbMotionFlag may be derived by the following equation.

subPbMotionFlag = (N = = TSUB) || (N = = SSUB) | | (N = = AFFINE) | | (N = = MAT)
Here, || indicates a logical sum (same below).

  Further, the image decoding device 31 and the image encoding device 11 may be configured to perform partial prediction among the spatial sub block prediction SSUB, the temporal sub block prediction TSUB, the affine prediction AFFINE, and the matching prediction MAT. That is, when the image coding apparatus 11 is configured to perform spatial sub-block prediction SSUB and affine prediction AFFINE, the sub-block prediction mode flag subPbMotionFlag may be derived as follows.

subPbMotionFlag = (N == SSUB) || (N = = AFFINE)
Note that the image decoding device 31 and the image encoding device 11 may decode the affine application flag pu_affine_enable_flag from the encoded data, and when the affine application flag pu_affine_enable_flag is 1, the subPbMotionFlag may be derived as 1. In this case, when the affine application flag pu_affine_enable_flag is 1, the affine prediction unit 30372 may be applied.

(Sub-block prediction unit)
Next, the sub-block prediction unit will be described.

(Space-time sub-block prediction unit 30371)
The spatio-temporal sub-block prediction unit 30371 uses the motion vector of the PU on the reference image (for example, the immediately preceding picture) temporally adjacent to the target PU or the motion vector of the PU spatially adjacent to the target PU To derive the motion vector of the subblock obtained by dividing. Specifically, by scaling the motion vector of the PU on the reference image to the reference picture to which the target PU refers, the motion vector spMvLX [xi] [yj] (xi = xPb) of each subblock in the target PU + nSbW * i, yj = yPb + nSbH * j, i = 0, 1, 2, ..., nPbW / nSbW-1, j = 0, 1, 2, ..., nPbH / nSbH-1) Derive (time sub-block prediction). Here, (xPb, yPb) is the upper left coordinate of the target PU, nPbW, nPbH is the size of the target PU, and nSbW, nSbH are the sizes of the subblocks.

  Also, by calculating a weighted average according to the distance between the motion vector of the PU adjacent to the target PU and the sub-block obtained by dividing the target PU, the motion vector spMvLX [of each sub-block in the target PU is calculated. xi] [yj] (xi = xPb + nSbW * i, yj = yPb + nSbH * j, i = 0, 1, 2, ..., nPbW / nSbW-1, j = 0, 1, 2, ... , NPbH / nSbH-1) may be derived (space sub-block prediction).

  The above candidate TSUB for temporal sub-block prediction and candidate SSUB for spatial sub-block prediction are selected as one mode (merge candidate) of merge mode.

(Affine Prediction Unit)
The affine prediction unit 30372 derives affine prediction parameters of the target PU. In this embodiment, motion vectors of two or three control points of the target PU are derived as affine prediction parameters. For example, in the case of three control points (V0, V1, V2), motion vectors (MV0_x, MV0_y) (MV1_x, MV1_y) (MV2_x, MV2_y) are derived.

  Specifically, the motion vector of each control point may be derived by predicting from the motion vector of the PU adjacent to the target PU, or the difference vector mvdLX derived from the prediction vector mvpLX of the control point and the coded data The motion vector of each control point may be derived by the sum of

  FIG. 13 shows the motion vector spMvLX of each sub block (xi, yj) constituting the target PU (nPbW × nPbH) from the motion vector (MV0_x, MV0_y) of the control point V0 and the motion vector (MV1_x, MV1_y) of V1. It is a figure which shows the example to derive | lead-out. The motion vector spMvLX of each sub block is derived as a motion vector for each point located at the center of each sub block, as shown in FIG.

  The affine prediction unit 30372 calculates the motion vector spMvLX [xi] [yj] of each subblock in the target PU based on the affine prediction parameter of the target PU (xi = xPb + nSbW * i, yj = yPb + nSbH * j, i = 0, 1, 2, ..., nPbW / nSbW-1, j = 0, 1, 2, ..., nPbH / nSbH-1) are derived using the following equation.

spMvLX [xi] [yj] [0] = MV0_x + (MV1_x-MV0_x) / nPbW * (xi + nSbW / 2)-(MV1_y-MV0_y) / nPbH * (yj + nSbH / 2)
spMvLX [xi] [yj] [1] = MV0_y + (MV1_y-MV0_y) / nPbW * (xi + nSbW / 2) + (MV1_x-MV0_x) / nPbH * (yj + nSbH / 2)
Here, xPb and yPb are the upper left coordinates of the target PU, nPbW and nPbH are the width and height of the target PU, and nSbW and nSbH are the width and height of the subblock.

(Flow of processing)
Hereinafter, as an example of a more specific implementation configuration, the flow of processing in which the affine prediction unit 30372 or the AMVP prediction parameter derivation unit 3032 derives the motion vector mvLX of each sub block using affine prediction is divided into steps and described Do. The process in which the affine prediction unit 30372 or the AMVP prediction parameter derivation unit 3032 derives the motion vector mvLX of the sub block using affine prediction includes the following four steps (STEP 1) to (STEP 4).

(STEP 1) Derivation of Control Point Vector As the two or more control points used by the affine prediction unit 30372 or the AMVP prediction parameter derivation unit 3032 for affine prediction for deriving a candidate, representative points of the target block (here, V0 and V1) ) Is a step of deriving each motion vector. The representative point of the block is a point on the target block or a point near the target block. In this specification, a representative point of a block used as a control point of affine prediction is referred to as a "block control point". Control points of affine prediction that are not representative points of blocks are sometimes referred to as “reference control points” and may be distinguished.

(STEP 2) Derivation of Sub-Block Vector From the motion vector of the block control point (control point V0 and V1), which is a representative point of the target block derived in STEP 1, the affine prediction unit 30372 or the AMVP prediction parameter derivation unit 3032 It is a process of deriving a motion vector of each included sub block. The motion vector mvLX of each sub block is derived by (STEP 1) and (STEP 2).

(STEP 3) Sub-block motion compensation Based on the prediction list use flag predFlagLX, the reference picture index refIdxLX, and the motion vector mvLX input from the inter prediction parameter decoding unit 303, the motion compensation unit 3091 generates a reference picture from the reference picture memory 306 Motion compensation is performed on a subblock basis to generate a motion compensated image predSamplesLX by reading and filtering a block located at a position shifted by the motion vector mvLX from the position of the target block on the reference picture specified by the index refIdxLX It is a process.

(STEP 4) Storage of motion vector of sub block In the case of the AMVP mode, the motion vector mvLX of each sub block derived by the AMVP prediction parameter deriving unit 3032 in the above (STEP 2) is stored in the prediction parameter memory 307. Similarly, also in the merge mode, the motion vector mvLX of each sub block derived by the affine prediction unit 30372 in (STEP 2) above is stored in the prediction parameter memory 307.

  Derivation of the sub-block motion vector mvLX using affine prediction can be performed in both the AMVP mode and the merge mode. Hereinafter, some processes of (STEP 1) to (STEP 4) will be described in the case of the AMVP mode and the case of the merge mode, respectively.

(STEP 1 details)
First, regarding the process of (STEP 1), the AMVP mode and the merge mode will be respectively described below with reference to FIG. FIG. 15 is a diagram showing an example of the position of a prediction unit used for deriving motion vectors of control points in the AMVP mode and the merge mode.

(Derivation of motion vector of control point in AMVP mode)
The AMVP prediction parameter derivation unit 3032 derives the vector candidate mvpLX from the motion vector stored in the prediction parameter memory 307 based on the reference picture index refIdx. Then, the AMVP prediction parameter derivation unit 3032 predicts (deduces) a motion vector of a representative point of the target block (here, the point V0, the point V1, and the point V2) with reference to the read motion vector.

  In the AMVP mode, the inter prediction parameter decoding control unit 3031 extracts AMVP prediction parameters from the coded data using the entropy decoding unit 301. This AMVP prediction parameter includes separately encoded difference vector mvdLX for correcting the prediction vector mvpLX of the representative points (point V0, point V1 and point V2).

  As shown in (a) of FIG. 15, the AMVP prediction parameter derivation unit 3032 is adjacent to one of the representative points (here, the point V0), and blocks A and B that share the representative point (apex) with the target block. And a motion vector of C (reference block) are referred to from the prediction parameter memory 307 to derive a prediction vector mvpLX of a representative point. Furthermore, the difference vector mvdLX of the representative point decoded from the encoded data is added to the derived predicted vector mvpLX to derive the motion vector mvLX of the control point V0. Note that the AMVP prediction parameter derivation unit 3032 may decode the index mvp_LX_idx from the encoded data to determine which one of the motion vectors of the blocks A, B, and C to refer to as a prediction vector.

  Similarly, as shown in (a) of FIG. 15, the AMVP prediction parameter derivation unit 3032 is adjacent to the representative point (here, point V1) different from the point V0, and the target block and the representative point (vertex) The prediction vector mvpLX of the representative point V1 is derived with reference to any one of the motion vectors of the blocks D and E (reference blocks) to be shared from the prediction parameter memory 307. Furthermore, the motion vector mvLX of the control point V1 is derived by adding the difference vector mvdLX of the representative point V1 decoded from the encoded data to the derived predicted vector mvpLX. Note that the AMVP prediction parameter derivation unit 3032 may decode the index mvp_LX_idx from the encoded data and determine which of the motion vectors of the blocks D and E to refer to as a prediction vector.

  Similarly, as shown in (b) of FIG. 15, the AMVP prediction parameter derivation unit 3032 is adjacent to a representative point (here, point V2) different from the points V0 and V1, and the target block and the representative point (vertex ) Is referred to from the prediction parameter memory 307 to derive a prediction vector mvpLX of the representative point V2. Furthermore, the AMVP prediction parameter derivation unit 3032 derives the motion vector mvLX of the control point V2 by adding the difference vector mvdLX of the representative point V2 decoded from the encoded data to the derived prediction vector mvpLX. Note that the AMVP prediction parameter derivation unit 3032 may decode the index mvp_LX_idx from the encoded data to determine which one of the motion vectors of the blocks F and G is to be referred to as a prediction vector.

  More specifically, the AMVP prediction parameter derivation unit 3032 derives prediction vector candidates for the control point VN (N = 0.2), and stores the prediction vector candidate list in the prediction vector candidate list mvpList VNLX []. Further, the AMVP prediction parameter derivation unit 3032 derives the motion vector (MVi_x, MVi_y) of the control point VN from the encoded data using the prediction vector index mvpVN_LX_idx of the point VN and the difference vector mvdVNLX according to the following equation.

MVi_x = mvLX [0] = mvpList VNLX [mvp VN_LX_idx] [0] + mvd VNLX [0]
MVi_y = mvLX [1] = mvpList VNLX [mvp VN_LX_idx] [1] + mvd VNLX [1]
The position of the control point in STEP 1 is not limited to the above. A lower right vertex of the target block or a point around the target block may be used as described later.

  As will be described later, in the configuration in which 4 parameter affine and 6 parameter affine are switched, AMVP prediction parameter derivation unit 3032 encodes difference vectors of two points, for example, points V0 and V1 in the case of 4 parameters affine. Decode from to derive motion vectors of two control points. In the case of six-parameter affine, difference vectors of three points, for example, points V0, V1, and V2 are decoded from the encoded data to derive motion vectors of three control points. The control points derived in the case of the four-parameter affine are not limited to the points V0 and V1, but may be the points V0 and V2, the points V1 and V2, the points V0 and V2, or two other points. Also in the case of six-parameter affine, the control points to be derived are not limited to the points V0, V1, and V2.

(General formula of affine prediction)
The general formula of the four-parameter affine is described below. The motion vector (MVi_x, MVi_y) of the point Vi at the position (xi, yi) starting from the point V0 of the motion vector mv_x, my_y at the position (0, 0) has four parameters (mv_x, mv_y, ev, rv) That is, using the motion vector of the enlargement and rotation center (translation vector mv_x, mv_y), the enlargement parameter ev, and the rotation parameter rv, it can be obtained by the following general equation (eq1).

MVi_x = mv_x + ev * xi-rv * yi
MVi_y = mv_y + rv * xi + ev * yi (eq1)
Note that the motion vectors (MV0_x, MV0_y) of the points of (xi, yi) = (0, 0) and the motion vectors (MVk_x, MVk_y) of the points of (xi, yi) = (xk, yk) are substituted into the above. When solving for (ev, rv), the following equation is obtained.

ev = {xk * (MVk_x-MV0_x) + yk * (MVk_y-MV0_y)} / (pow (xk, 2) + pow (yk, 2))
rv = {-yk * (MVk_x-MV0_x) + xk * (MVk_y-MV0_y)} / (pow (xk, 2) + pow (yk, 2))
Note that pow (x, 2) represents the square of x.

  Subsequently, the general formula of the six-parameter affine will be described below. The motion vector (MVi_x, MVi_y) of the point Vi at the position (xi, yi) starting from the point V0 of the position (0, 0), motion vector mv_x, my_y has four parameters (mv_x, mv_y, ev1, rv1, It can be determined by the following general formula (eq2) using ev2, rv2).

MVi_x = mv_x + ev1 * xi + rv2 * yi
MVi_y = mv_y + rv1 * xi + ev2 * yi (eq2)
(Derivation of control point motion vector in merge mode)
For a prediction unit including blocks A to E as shown in (c) of FIG. 15, the affine prediction unit 30372 refers to the prediction parameter memory 307 and confirms whether affine prediction is used. A prediction unit (here, reference block A in FIG. 15C) which is first found as a prediction unit in which affine prediction is used is selected as an adjacent block (merge reference block) to derive a motion vector. The adjacent block does not have to be in direct contact with the target PU (there is no need to have a common side). For example, a block that shares a point with the target PU, such as the upper right point or the upper left point of the target PU, or the lower right point, can also be an adjacent block. Also, neighboring blocks sufficiently close to the target PU can be used as neighboring blocks. The same applies to the second to fifth embodiments described later.

  The affine prediction unit 30372 uses affine prediction and is located at the upper left corner point (point v0 of (d) of FIG. 15) and the upper right corner point ((d) of FIG. 15) of the selected adjacent block. The motion vector of the control point is derived from the point v1), and the lower left corner point (point v2 in (d) of FIG. 15) and the lower right point v3 from each of two or three points. In the case of the four-parameter affine, in one example, motion vectors of V0 (first control point) and V1 (second control point) are derived. Also, in the case of a six-parameter affine, motion vectors of V0, V1, and V2 (third control points) are derived. In the example shown in (d) of FIG. 15, the width of the block for which the motion vector is to be predicted is W and the height is H, and the adjacent block (the adjacent block including the block A in the illustrated example) The width is w and the height is h.

  In the 4-parameter affine, the motion vector (MVN_x, MVN_y) of the control point VN (N = 0.1) is derived by the following equation.

MVN_x = mv_x + ev * xN-rv * yN
MVN_y = mv_y + rv * xN + ev * yN
Here, (ev, rv) is an affine parameter, and (xN, yN) is a relative position viewed from a reference point (for example, v0) of the control point VN. mv_x and mv_y are translation vectors, for example, a motion vector (mv0_x, mv0_y) of a point v0. The translation vector is not limited to (mv0_x, mv0_y), and motion vectors (mv1_x, mv1_y), (mv2_x, mv2_y), (mv3_x, mv3_y) of points v1, v2, and v3 may be used.

The relative position of the point Vi starting from the point v0 is derived as follows. First, if the position of the point v0 is (xRef, yRef) and the position of the point Vi is (xPi, yPi), the relative position (xi, yi) of the point Vi starting from the point v0 is from the position of the point Vi From the difference in position with the origin v0,
xi = xPi-xRef
yi = yPi-yRef
It becomes. In the above example, the position of point v0 is (xP-w, yP + H-h), and the positions of points V0, V1 and V2 are respectively (xP, yP), (xP + W, yP), (xP, (xP, w) Since yP + H), the relative position (xi, yi) (where i = 0 .. 2) of the point Vi starting from the point v0 is derived as follows.

x0 = xP0-xRef = xP-(xP-w) = w
y0 = yP0-yRef = yP-(yP + H-h) = h-H
x1 = xP1-xRef = (xP + W)-(xP-w) = w + W
y1 = yP1-yRef = yP-(yP + H-h) = h-H
x2 = xP2-xRef = xP-(xP-w) = w
y2 = yP2-yRef = (yP + H)-(yP + H-h) = h
Also, the affine prediction unit 30372 may derive (MVN_x, MVN_y) by integer operation using the following equation.

MVN_x = mv_x + ((evBW-rvBH) >> 1) + evBW * iN-rvBH * jN
MVN_y = mv_y + ((rvBW + evBH) >> 1) + rvBW * iN + evBH * jN
Here, (evBW, rvBW) and (evBH, rvBH) are affine parameters, and (iN, jN) are coordinates in units of sub blocks of the control point VN. For example, (iN, jN) = (xN >> log2 (W), yN >> log2 (H)). Here, W and H are the width and height of the subblock.

  In the six parameter affine, the motion vector of the control point is derived by the following equation.

MVN_x = mv_x + ev1 * xN + rv2 * yN
MVN_y = mv_y + rv1 * xN + ev2 * yN
Here, (ev1, rv1, ev2, rv2) are affine parameters.

  Also, the affine prediction unit 30372 may derive (MVN_x, MVN_y) by integer operation using the following equation.

MVN_x = mv_x + ((ev1BW + rv2BH) >> 1) + ev1BW * iN + rv2BH * jN
MVN_y = mv_y + ((rv1BW + ev2BH) >> 1) + rv1BW * iN + ev2BH * jN
Here, (ev1BW, rv1BW, ev2BH, ev2BH) are affine parameters.

  The derivation method of the above affine parameters (ev, rv), (evBW, rvBW), (evBH, rvBH), (ev1, rv1, ev2, rv2), (ev1BW, rv1BW, ev2BH, ev2BH) is described in (STEP 2 details) I will mention later. At the time of derivation, control points V0, V1, V2 and V3 are respectively replaced with reference points v0, v1, v2 and v3 on adjacent blocks, and motion vectors of control points (MV1_x, MV1_y), (MV2_x, MV2_y) And (MV3_x, MV3_y) are replaced with motion vectors (mv0_x, mv0_y), (mv1_x, mv1_y), (mv2_x, mv2_y), and (mv3_x, mv3_y) of reference points, respectively.

  In addition, the affine prediction unit 30372 calculates representative points on the target block from the motion vectors (mv0_x, mv0_y), (mv1_x, mv1_y), and (mv2_x, mv2_y) of the points v0, v1 and v2 in (d) in FIG. Motion vectors of (control points V0, V1 and V2) may be derived. The derivation equation is as follows.

MVi_x = mv0_x + (mv1_x-mv0_x) / w * xi + (mv2_x-mv0_x) / h * yi
MVi_y = mv0_y + (mv1_y-mv0_y) / w * xi + (mv2_y-mv0_y) / h * yi
Here, (xi, yi) are coordinates of points to be derived (here, control points V0, V1 and V2) starting from the point v0, and w and h are respectively the reference point v1 and the base reference point v0. This corresponds to the distance (= X coordinate of point v1−X coordinate of point v0), distance between reference point v2 and base reference point v0 (= Y coordinate of point v2−Y coordinate of point v0).

The position (x0, y0) = (w, h-H) of the point V0 starting from the point v0 of the base reference point and the position (x1, y1) = (w, h1) of the point V1 Substituting w + W, h-H) to derive the motion vector of point V0 (MV0_x, MV0_y) and the motion vector of point V1 (MV1_x, MV1_y),
MV0_x = mv0_x + (mv1_x-mv0_x) / w * w + (mv2_x-mv0_x) / h * (h-H)
MV0_y = mv0_y + (mv1_y-mv0_y) / w * w + (mv2_y-mv0_y) / h * (h-H)
MV1_x = mv0_x + (mv1_x-mv0_x) / w * (w + W) + (mv2_x-mv0_x) / h * (h-H)
MV1_y = mv0_y + (mv1_y-mv0_y) / w * (w + W) + (mv2_y-mv0_y) / h * (h-H)
It becomes.

  In STEP1, the selection of control points is not limited to the above.

  The affine prediction unit 30372 of this configuration derives the motion vector of the control point (V0, V1, V2, V3) from the motion vector of the reference point (v0, v1, v2, v3) of the adjacent block in (STEP1) In (STEP 2), the motion vector of the sub block is derived from the motion vector of the control point (V0, V1, V2, V3), but (STEP 1) and (STEP 2) are integrated to form an adjacent block. The motion vector of the subblock may be derived from the motion vector of the reference point (v0, v1, v2, v3) of

(STEP 2 details)
Subsequently, the process of (STEP 2) will be described with reference to FIG. FIG. 16 is a diagram showing an example in which the control point V0 of the target block (horizontal width W, height H) is located at the top left corner and is divided into sub-blocks of width BW and height BH. (W, H) and (BW, BH) correspond to (nPbW, nPbH) and (nSbW, nSbH) described above.

The affine prediction unit 30372 (AMVP prediction parameter derivation unit 3032) refers to the motion vector of two or three control points among the control points V0, V1 and V2 which are representative points on the block derived in (STEP 1) In (STEP 2), affine parameters are calculated. That is, the affine prediction unit 30372 (AMVP prediction parameter derivation unit 3032) performs any of the following processing.
-From two motion vectors among the motion vector of control point V0 (MV0_x, MV0_y), the motion vector of control point V1 (MV1_x, MV1_y), and the motion vector of control point V2 (MV2_x, MV2_y), affine parameters (ev, rv) Derive).
From the three motion vectors of the motion vector of control point V0 (MV0_x, MV0_y), the motion vector of control point V1 (MV1_x, MV1_y) and the motion vector of control point V2 (MV2_x, MV2_y), affine parameters (ev1, rv1, Derivate ev2, ev2).

  In the following description, the process of deriving affine parameters (ev, rv) from two motion vectors is referred to as “four-parameter affine”. The process of deriving affine parameters (ev1, rv1, ev2, ev2) from three motion vectors is referred to as "6-parameter affine".

  Affine parameters can also be treated as integers rather than decimals. The following are the affine parameters of decimal places (ev, rv), (ev1, rv1, ev2, ev2) and integer affine parameters (evBW, rvBW), (evBH, rvBH), (ev1BW, rv1BW, ev2BH, ev2BH) Express as

  The integer affine parameter is obtained by multiplying the affine parameter of the decimal point number by a constant (integerization constant) according to the sub block size (BW, BH). Specifically, there are the following relationships between the decimal affine parameters and the integer affine parameters.

evBW = ev * BW = ev << log 2 (BW)
rvBW = rv * BW = rv << log 2 (BW)
evBH = ev * BH = ev << log 2 (BH)
rv BH = rv * BH = rv << log 2 (BH)
ev1BW = ev1 * BW = ev1 << log2 (BW)
rv1BW = rv1 * BH = rv1 << log2 (BW)
ev2BH = ev2 * BW = ev2 << log2 (BH)
rv2BH = rv2 * BH = rv2 << log2 (BH)
When the width BW and the height BH of the sub-block are equal, (evBW, rvBW) = (evBH, rvBH), and therefore, it is not necessary to distinguish between (evBW, rvBW) and (evBH, rvBH). That is, in the following derivation of affine parameters, it is sufficient to derive only (evBW, rvBW) or only (evBH, rvBH).

For example, when using the motion vectors of control points V0 and V1, the affine prediction unit 30372 (AMVP prediction parameter derivation unit 3032) uses the following equation for the affine parameters,
evBW = (MV1_x-MV0_x) >> shiftWBW
rvBW = (MV1_y-MV0_y) >> shiftWBW
evBH = (MV1_x-MV0_x) >> shiftWBH
rvBH = (MV1_y-MV0_y) >> shiftWBH
shiftWBW = log2 (W)-log2 (BW)
shiftHBH = log2 (H)-log2 (BH)
To derive.

In addition, when using the affine parameter of the decimal point number, using the following formula,
ev = (MV1_x-MV0_x) / W
rv = (MV1_y-MV0_y) / W
It may be derived as In this equation, the position of the control point V0 of the general formula is (0, 0), and the position of the control point V1 is (W, 0).

In addition, when using the motion vectors of control points V0 and V2, the affine prediction unit 30372 (AMVP prediction parameter derivation unit 3032) uses the following equation for the affine parameter,
evBW = (MV2_y-MV0_y) >> shiftHBW
rvBW =-(MV2_x-MV0_x) >> shiftHBW
evBH = (MV2_y-MV0_y) >> shiftHBH
rvBH =-(MV2_x-MV0_x) >> shiftHBH
shiftHBW = log2 (H)-log2 (BW)
shiftHBH = log2 (H)-log2 (BH)
To derive. Note that this equation is a derivation equation for the affine parameter of the following decimal places
ev = (MV2_y-MV0_y) / H
rv =-(MV2_x-MV0_x) / H
Equal to

Further, in the case of using the motion vectors of control points V1 and V2, the affine prediction unit 30372 (AMVP prediction parameter derivation unit 3032) uses the following equation for the affine parameters,
evBW = {(MV1_x-MV2_x)-(MV1_y-MV2_y)} >> (shiftWBW + 1)
rvBW = {(MV1_x-MV2_x) + (MV1_y-MV2_y)} >> (shiftWBW + 1)
evBH = {(MV1_x-MV2_x)-(MV1_y-MV2_y)} >> (shiftWBH + 1)
rvBH = {(MV1_x-MV2_x) + (MV1_y-MV2_y)} >> (shiftWBH + 1)
To derive. Note that this equation is a derivation equation for the affine parameter of the following decimal places
ev = {(MV1_x-MV2_x)-(MV1_y-MV2_y)} / 2W
rv = {(MV1_x-MV2_x) + (MV1_y-MV2_y)} / 2W
Equal to

Also, a motion vector of a control point V3 (a control point located diagonally to V0 in the target block), which is different from any of the control points V0 to V2 described above, can be used. For example, when using the motion vectors of control points V0 and V3, the affine prediction unit 30372 (AMVP prediction parameter derivation unit 3032) uses the following equation for the affine parameters,
evBW = (MV3_x-MV0_x + MV3_y-MV0_y) >> (shiftWBW + 1)
rvBW = (-MV3_x + MV0_x + MV3_y-MV0_y) >> (shiftWBW + 1)
evBH = (MV3_x-MV0_x + MV3_y-MV0_y) >> (shiftWBH + 1)
rvBH = (-MV3_x + MV0_x + MV3_y-MV0_y) >> (shiftWBH + 1)
To derive. Note that this equation is a derivation equation for the affine parameter of the following decimal places
ev = (MV3_x-MV0_x + MV3_y-MV0_y) / 2W
rv = (-MV3_x + MV0_x + MV3_y-MV0_y) / 2W
Equal to

When three motion vectors of control points V0, V1 and V2 are used, the affine prediction unit 30372 (AMVP prediction parameter derivation unit 3032) uses the following equation for the affine parameter,
ev1BW = (MV1_x-MV0_x) >> shiftWBW
rv2BH = (MV2_x-MV0_x) >> shiftHBH
rv1BW = (MV1_y-MV0_y) >> shiftWBW
ev2BH = (MV2_y-MV0_y) >> shiftHBH
shiftWBW = log2 (W)-log2 (BW)
shiftHBH = log2 (H)-log2 (BH)
To derive. Note that this equation is a derivation equation for the affine parameter of the following decimal places
ev1 = (MV1_x-MV0_x) / W
rv2 = (MV2_x-MV0_x) / H
rv1 = (MV1_y-MV0_y) / W
ev2 = (MV2_y-MV0_y) / H
Equal to

(Derivation of motion vector of subblock)
The affine prediction unit 30372 (AMVP prediction parameter derivation unit 3032) derives the motion vector of the sub block using the affine parameters obtained by the above equation.

  In the case of the four-parameter affine, the motion vector (MVi_x, MVi_y) of the subblock of the subblock coordinates (xi, yi) is derived from the affine parameter (ev, rv) by the following equation AF4P_float.

MVi_x = mv_x + ev * xi-rv * yi
MVi_y = mv_y + rv * xi + ev * yi (expression AF4P_float)
Although (MV0_x, MV0_y) may be used as the translation vector affine parameters mv_x and mv_y, it is not limited thereto. For example, motion vectors (MV1_x, MV1_y), (MV2_x, MV2_y), and (MV3_x, MV3_y) other than (MV0_x, MV0_y) may be used as translation vectors. In particular, when V1 and V2 are set as control points, it is preferable to set the motion vector of V1 (MV1_x, MV1_y) or the motion vector of V2 (MV2_x, MV2_y) as a translation vector.

  Also, if the affine parameters are integer affine parameters (evBW, rvBW) and (evBH, rvBH), the motion vector (MVij_x, MVij_y) of the subblock at subblock position (i, j) is derived by the following formula AF4P_integer Do.

MVij_x = mv_x + ((evBW-rvBH) >> 1) + evBW * i-rvBH * j
MVij_y = mv_y + ((rvBW + evBH) >> 1) + rvBW * i + evBH * j (Expression AF4P_integer)
When (MV0_x, MV0_y) is used as a translation vector, the above equation becomes the following equation.

MVij_x = MV0_x + ((evBW-rvBH) >> 1) + evBW * i-rvBH * j
MVij_y = MV0_y + ((rvBW + evBH) >> 1) + rvBW * i + evBH * j
When the sub-block width BW and height BH are equal, (evBW, rvBW) = (evBH, rvBH)
Therefore, it is not necessary to distinguish between (evBW, rvBW) and (evBH, rvBH) in the above derivation formula. That is, it may be derived from only (evBW, rvBW).

MVij_x = mv_x + ((evBW + rvBW) >> 1) + evBW * i-rvBW * j
MVij_y = mv_y + ((rvBW + evBW) >> 1) + rvBW * i + evBW * j
Alternatively, it may be derived from (evBH, rvBH) alone.

MVij_x = mv_x + ((evBH + rvBH) >> 1) + evBH * i-rvBH * j
MVij_y = mv_y + ((rvBH + evBH) >> 1) + rvBH * i + evBH * j
Here, the relationship between the subblock position (i, j) and the subblock coordinates (xi, yj) is as follows (equation XYIJ).

xi = BW / 2 + BW * i
yj = BH / 2 + BH * j (formula XYIJ)
i = 0 .. (B / SW) -1, j = 0 .. (H / SH) -1
The point at the sub block position (i, j) is an intersection point of a solid line parallel to the x axis in FIG. 16 and a solid line parallel to the y axis. The point of the subblock coordinates (xi, yj) is an intersection point of a broken line parallel to the x axis in FIG. 16 and a broken line parallel to the y axis. FIG. 16 shows, as an example, a point of sub block position (i, j) = (1, 1) and a point of sub block coordinates (x1, y1) with respect to the sub block position.

It should be noted that an equation for deriving an integer can be obtained from the equation for deriving a decimal point by the following modification. Substituting the above equation XYIJ into (xi, yi) of the above-mentioned decimal point equation AF4P_float,
MVij_x = mv_x + ev * (BW / 2 + BW * i)-rv * (BH / 2 + BH * j)
MVij_y = mv_y + rv * (BW / 2 + BW * i) + ev * (BH / 2 + BH * j)
It becomes. Further deformation
MVij_x = mv_x + ev * BW * (1/2 + i)-rv * BH * (1/2 + j)
MVij_y = mv_y + rv * BW * (1/2 + i) + ev * BH * (1/2 + j)
It becomes. Further, when deformed by ev * BW = evBW, rv * BH = rvBH, rv * BW = rvBW, ev * BH = evBH,
MVij_x = MV0_x + evBW * (1/2 + i)-rvBH * (1/2 + j)
MVij_y = MV0_y + rvBW * (1/2 + i) + evBH * (1/2 + j)
It becomes. Further deformation
MVij_x = MV0_x + evBW / 2-rvBH / 2 + evBW * i-rvBH * j
MVij_y = MV0_y + rvBW / 2 + evBH / 2 + rvBW * i + evBH * j
Finally, the above-mentioned integer arithmetic expression AF4P_integer
MVij_x = mv_x + ((evBW-rvBH) >> 1) + evBW * i-rvBH * j
MVij_y = mv_y + ((rvBW + evBH) >> 1) + rvBW * i + evBH * j
It becomes. It is preferable to use (MV0_x, MV0_y) as the translation vector affine parameters mv_x and mv_y, but is not limited thereto. For example, motion vectors (MV1_x, MV1_y), (MV2_x, MV2_y), and (MV3_x, MV3_y) may be translation vectors.

In the case of the six-parameter affine, from the affine parameters (ev1, rv1, ev2, ev2), the motion vector (MVij_x, MVij_y) of the subblock of the subblock coordinates (xi, yi) is expressed by the following formula AF6P_float
MVij_x = mv_x + ev1 * xi + rv2 * yi
MVij_y = mv_y + rv 1 * xi + ev 2 * yi (equation AF6P_float)
To derive.

  When the affine parameters (ev1, rv1, ev2, ev2) are integer affine parameters (ev1BW, rv1BH, ev2BW, ev2BH), the motion vector (MVij_x, MVij_y) of the subblock at subblock position (i, j) ) Is derived by the following equation AF6P_integer.

MVij_x = mv_x + ((ev1BW + rv2BH) >> 1) + ev1BW * i + rv2BH * j
MVij_y = mv_y + ((rv1BW + ev2BH) >> 1) + rv1BW * i + ev2BH * j (Expression AF6P_integer)
For example, when (MV0_x, MV0_y) is used as a translation vector, the above equation becomes the following equation.

MVij_x = MV0_x + ((ev1BW + rv2BH) >> 1) + ev1BW * i + rv2BH * j
MVij_y = MV0_y + ((rv1BW + ev2BH) >> 1) + rv1BW * i + ev2BH * j (Expression AF6P_integer)
It should be noted that an equation for deriving an integer can be obtained from the equation for deriving a decimal point by the following modification. Substituting the above equation XYIJ into (xi, yi) of the above-mentioned decimal point equation AF6P_float, and modifying the equation,
MVij_x = mv_x + ev1 * (BW / 2 + BW * i) + rv2 * (BH / 2 + BH * j)
MVij_y = mv_y + rv1 * (BW / 2 + BW * i) + ev2 * (BH / 2 + BH * j)
It becomes. Further deformation
MVij_x = mv_x + ev1 * BW * (1/2 + i) + rv2 * BH * (1/2 + j)
MVij_y = mv_y + rv1 * BW * (1/2 + i) + ev2 * BH * (1/2 + j)
It becomes. Furthermore, when deformed by ev1 * BW = ev1BW, rv2 * BH = rv2BH, rv1 * BW = rv1BW, ev2 * BH = ev2BH,
MVij_x = mv_x + ev1BW * (1/2 + i) + rv2BH * (1/2 + j)
MVij_y = mv_y + rv1BW * (1/2 + i) + ev2BH * (1/2 + j)
It becomes. Further deformation
MVij_x = mv_x + ev1BW / 2 + rv2BH / 2 + ev1BW * i + rv2BH * j
MVij_y = mv_y + rv1BW / 2 + ev2BH / 2 + rv1BW * i + ev2BH * j
Finally, the above-mentioned integer arithmetic derivation expression AF6P_integer
MVij_x = mv_x + ((ev1BW + rv2BH) >> 1) + ev1BW * i + rv2BH * j
MVij_y = mv_y + ((rv1BW + ev2BH) >> 1) + rv1BW * i + ev2BH * j
It becomes.

(Determination of control point)
The inter prediction parameter decoding unit 303 determines which of the four-parameter affine and the six-parameter affine to execute by a predetermined process. An example of the predetermined process is shown below. In the flowcharts used in the following description, puWidth indicates the width of the target PU, and puHeight indicates the height of the target PU. (PuWidth, puHeight) correspond to (nPbW, nPbH) described above.

(Determined by the shape of the target PU)
FIG. 17 is a flowchart illustrating an example of processing in which the inter prediction parameter decoding unit 303 determines the number of control points for deriving a motion vector based on the shape of the target PU. In the example shown in FIG. 17, the inter prediction parameter decoding control unit 3031 first determines in the inter prediction parameter decoding unit 303 whether the width of the target PU and the height of the target PU are equal (SA1). If the width of the target PU and the height of the target PU are equal (Y in SA1), the affine prediction unit 30372 (or the AMVP prediction parameter decoding unit 3032) performs 6-parameter affine processing (SA2). If the width of the target PU and the height of the target PU are not equal (N in SA1), the affine prediction unit 30372 (or the AMVP prediction parameter decoding unit 3032) performs 4-parameter affine processing (SA3).

  The determination in SA1 is equivalent to determining whether the target PU is a square. That is, in the example shown in FIG. 17, processing of six parameter affine is performed when the target PU is a square, and processing of four parameter affine is performed when the target PU is not a square.

  Further, the process of deriving the motion vector based on the shape of the target PU may be applied only in the merge mode or only in the AMVP. FIG. 18 is a flowchart showing another example of processing in which the affine prediction unit 30372 determines the number of control points for deriving a motion vector based on the shape of the target PU. In the example illustrated in FIG. 18, prior to the process of SA1 illustrated in FIG. 17, the inter prediction parameter decoding control unit 3031 determines whether the merge flag is 1 (SB1). When the merge flag is 1, that is, in the merge mode (Y in SB1), the inter prediction parameter decoding unit 303 performs the processing of SB2 to SB4. The processes of SB2 to SB4 are the same as the processes of SA1 to SA3 shown in FIG. On the other hand, when the merge flag is 0, that is, when not in the merge mode (N in SB1), the inter prediction parameter decoding unit 303 performs motion vector derivation processing of AMVP.

  Note that, in the example illustrated in FIG. 18, when the merge flag is 1, the affine prediction unit 30372 derives an affine parameter in accordance with whether or not the target PU is a square. However, contrary to the example shown in FIG. 18, the affine prediction unit 30372 according to the present embodiment determines that the affine parameters are different depending on whether the target PU is square or not when the merge flag is 0, that is, when it is AMVP. It may be derived. In this case, derivation of the affine parameters is performed in the AMVP prediction parameter derivation unit 3032. Further, the motion vector of the control point is derived in accordance with the above-mentioned (derivation of the motion vector of the control point in the AMVP mode).

  Although not described above, the inter prediction parameter decoding unit 303 may decode the affine application flag pu_affine_enable_flag, which is a flag indicating whether to perform affine prediction. The inter prediction parameter decoding unit 303 performs an affine prediction process when the affine application flag pu_affine_enable_flag indicates 1, that is, indicates that affine prediction is applied, and does not apply the affine prediction when the affine application flag pu_affine_enable_flag is 0. .

  FIG. 19 is a flowchart showing yet another example of processing in which the inter prediction parameter decoding unit 303 determines the number of control points for deriving a motion vector based on the shape of a target PU.

  In the example shown in FIG. 19, in the case of AMVP, when the shape of the target PU is a square, the PU affine mode flag, which is a flag indicating a 6 parameter affine and a 4 parameter affine, is decoded; Do not decode the PU affine mode flag. More specifically, the inter prediction parameter decoding control unit 3031 first determines whether the merge flag is 1 (SC1). If the merge flag is 0 (indicating that the merge process is not performed) (N in SC1), the inter prediction parameter decoding control unit 3031 determines whether the width of the target PU is equal to the height of the target PU ( SC2). If the width of the target PU and the height of the target PU are equal (Y in SC2), the inter prediction parameter decoding control unit 3031 decodes the PU affine mode flag (SC3). Thereafter, the inter prediction parameter decoding control unit 3031 determines whether the PU affine mode flag is 1 (SC4).

  The AMVP prediction parameter derivation unit 3032 performs 6 parameter affine processing when the PU affine mode flag is 1 (showing that 6 parameter affine processing is to be performed) (Y in SC4), and the PU affine mode flag If 0 is 0 (N in SC4), 4-parameter affine processing is performed. The AMVP prediction parameter derivation unit 3032 also performs 4-parameter affine processing when the width of the target PU and the height of the target PU are not equal (N in SC2). On the other hand, when the merge flag is 1 (Y in SC1), motion vector derivation is performed by merge prediction.

  In this configuration, the inter prediction parameter decoding unit 303 calculates motion vectors of two control points according to the shape of the target block and performs four parameter affine processing, or calculates motion vectors of three control points. 6 Switch whether to process parameter affine. In the case of application to AMVP, at SC1, either two motion vectors (difference vectors) are encoded / decoded or three motion vectors (difference vectors) are encoded / decoded according to the shape of the target block. You may switch between When applying to merging, in SC1 the motion vector of the control point is derived by referring to the motion vector of 2 points according to the shape of the target block, or the motion of the control point is referred to by the motion vector of 3 points It may be switched whether to derive a vector. In SC2, whether to derive the motion vector of each sub block with reference to the motion vector of 2 points according to the shape of the target block or derive the motion vector of each sub block with reference to the motion vector of 3 points , May be switched.

(Decision by size of target PU)
FIG. 20 is a flowchart illustrating an example of processing in which the inter prediction parameter decoding unit 303 determines the number of control points for deriving a motion vector based on the size of the target PU. In the example illustrated in FIG. 20, the inter prediction parameter decoding control unit 3031 first determines whether the value indicating the size of the target PU is equal to or greater than a predetermined threshold (SD1). If the size of the target PU is equal to or greater than the predetermined threshold (Y in SD1), the affine prediction unit 30372 performs six-parameter affine processing (SD2). If the size of the target PU is not equal to or larger than the predetermined threshold (N in SD1), the affine prediction unit 30372 performs 4-parameter affine processing (SD3).

For example, the following can be used as a value indicating the size of the target PU.
Max (puWidth, puHeight)
・ Min (puWidth, puHeight)
-PuWidth + puHeight
・ PuWidth * puHeight
・ Log2 (puWidth) + log2 (puHeight)
However, the value indicating the size of the target PU is not limited to the above example.

Further, the determination in SD1 may be as follows.
Whether the size of the target PU is larger than a predetermined threshold value.
• Whether the size of the target PU is less than or equal to a predetermined threshold value.
• Whether the size of the target PU is smaller than a predetermined threshold.

  FIG. 21 is a flowchart illustrating another example of processing in which the inter prediction parameter decoding unit 303 determines the number of control points for deriving the motion vector based on the size of the target PU. In the example shown in FIG. 21, in the case of AMVP, the PU affine mode flag, which is a flag indicating 6 parameter affine and 4 parameter affine, is decoded to increase the size of the target PU; Do not decode mode flags. More specifically, as in the example shown in FIG. 19, the inter prediction parameter decoding control unit 3031 first determines whether the merge flag is 1 (SE1). If the merge flag is 0 (N in SE1), the inter prediction parameter decoding control unit 3031 determines whether the size of the target PU is equal to or more than a predetermined threshold (SE2). The inter prediction parameter decoding unit 303 performs the processing of SE3 to SE6 based on the determination result of SE2. The processes of SE3 to SE6 are similar to the processes of SC3 to SC6 shown in FIG.

  FIG. 22 is a table showing processing for each size when log2 (puWidth) + log2 (puHeight) is used as a value indicating the size of the target PU. In the example shown in FIG. 22, the threshold value for determination is eight. In this case, in the example shown in FIG. 22, if log2 (puWidth) + log2 (puHeight) is 6 or 7, the affine prediction unit 30372 performs 4-parameter affine processing regardless of the shape of the target PU. Further, if log2 (puWidth) + log2 (puHeight) is 8, the affine prediction unit 30372 performs 6-parameter affine processing regardless of the shape of the target PU.

  FIG. 23 is a table showing processing for each size when min (puWidth, puHeight) is used as a value indicating the size of the target PU. In the example shown in FIG. 23, the threshold value for determination is eight. In this case, as shown in FIG. 23, if min (puWidth, puHeight) is 4, the affine prediction unit 30372 performs the 4-parameter affine process regardless of the shape of the target PU. If min (puWidth, puHeight) is 8 or 16, the affine prediction unit 30372 performs 6-parameter affine processing regardless of the shape of the target PU.

  In this configuration, the inter prediction parameter decoding unit 303 calculates motion vectors of two control points according to the size of the target block and performs four parameter affine processing, or calculates motion vectors of three control points. 6 Switch whether to process parameter affine. When applied to AMVP, at SE1, either encode / decode two motion vectors (difference vectors) according to the size of the target block, or encode / decode three motion vectors (difference vectors) You may switch between When applying to merging, in SE1, the motion vector of the control point is derived by referring to the motion vector of 2 points according to the size of the target block, or the motion of the control point is referred to by the motion vector of 3 points It may be switched whether to derive a vector. In SE2, whether to derive the motion vector of each sub block with reference to the motion vector of 2 points according to the size of the target block or to derive the motion vector of each sub block with reference to the motion vector of 3 points , May be switched.

(Determined by shape and size of target PU)
FIG. 24 is a flowchart illustrating an example of processing in which the inter prediction parameter decoding unit 303 determines the number of control points for deriving a motion vector based on both the shape and the size of the target PU. In the example illustrated in FIG. 24, the inter prediction parameter decoding control unit 3031 first determines whether the size of the target PU is equal to or larger than a predetermined threshold (SF1). If the size of the target PU is equal to or larger than the predetermined threshold (Y in SF1), the affine prediction unit 30372 performs six-parameter affine processing (SF3).

  If the size of the target PU is not equal to or larger than the predetermined threshold (N in SF1), the inter prediction parameter decoding control unit 3031 continues to determine whether the width of the target PU and the height of the target PU are equal (SF2). If the width of the target PU and the height of the target PU are equal (Y in SF2), the affine prediction unit 30372 performs six-parameter affine processing (SF3). If the width of the target PU and the height of the target PU are not equal (N in SF2), the affine prediction unit 30372 performs 4-parameter affine processing (SF4).

  That is, in the example shown in FIG. 24, when the target PU is equal to or larger than a predetermined size or is a square, the affine prediction unit 30372 performs six parameter affine processing. On the other hand, when the target PU is smaller than a predetermined size and is not square, the affine prediction unit 30372 performs 4-parameter affine processing.

  FIG. 25 is a flowchart illustrating another example of processing in which the inter prediction parameter decoding unit 303 determines the number of control points for deriving a motion vector based on both the shape and the size of the target PU. In the example shown in FIG. 25, the inter prediction parameter decoding control unit 3031 first determines whether the merge flag is 1 (SG1), as in the examples shown in FIGS. If the merge flag is 0 (N in SE1), the inter prediction parameter decoding control unit 3031 determines the size and shape of the target PU, as in SF1 and SF2 shown in FIG. 24 (SG2, SG3). When the size of the target PU is equal to or larger than the predetermined threshold (Y in SG2), or when the size of the target PU is not equal to or larger than the predetermined threshold (N in SG2) and the target PU is square (Y in SG3), The affine prediction unit 30372 performs the processes of SG4 to SG7 (similar to SC3 to SC6 illustrated in FIG. 19).

  FIG. 26 is a table showing an example of processing of the affine prediction unit 30372 for each size and shape of the target PU. In the example illustrated in FIG. 26, log2 (puWidth) + log2 (puHeight) is used as a value indicating the size of the target PU, and the threshold is set to 8.

  In the example shown in FIG. 26, when the value indicating the size of the target PU is 6 or 7, the affine prediction unit 30372 has six parameters only when the symmetric PU is a square (8 * 8 in FIG. 26). Perform affine processing. Otherwise, the affine prediction unit 30372 performs four-parameter affine processing. On the other hand, when the size of the target PU is 8, the affine prediction unit 30372 performs six-parameter affine processing regardless of the shape of the target PU.

  FIG. 27 is a table illustrating another example of processing of the affine prediction unit 30372 for each size and shape of the target PU. In the example illustrated in FIG. 27, min (puWidth, puHeight) is used as a value indicating the size of the target PU, and the threshold is set to 16.

  In the example shown in FIG. 27, when the value indicating the size of the target PU is 4 or 8, the affine prediction unit 30372 has six parameters only when the target PU is a square (8 * 8 in FIG. 27). Perform affine processing. Otherwise, the affine prediction unit 30372 performs four-parameter affine processing. On the other hand, when the size of the target PU is 16, the affine prediction unit 30372 performs six-parameter affine processing.

  In this configuration, the inter prediction parameter decoding unit 303 calculates motion vectors of two control points and performs four parameter affine processing according to the shape and size of the target block, or calculates motion vectors of three control points. Switch whether to process 6 parameters affine. When applied to AMVP, SG1 encodes or decodes two motion vectors (difference vectors) according to the shape and size of the target block, or encodes three motion vectors (difference vectors) You may switch whether to decode. When applied to merging, SG1 refers to two motion vectors according to the shape and size of the target block to derive motion vectors of control points, or refers to three motion vectors to control points It may be switched whether to derive a motion vector of In SG2, the motion vector of each sub block is derived with reference to the motion vector of 2 points according to the shape and size of the target block, or the motion vector of each sub block is derived with reference to the motion vector of 3 points You may switch between.

(Matching prediction unit 30373)
The matching prediction unit 30373 derives the motion vector spMvLX of the sub-blocks constituting the PU by performing either the bilateral matching or the template matching. FIG. 14 is a diagram for explaining (a) Bilateral matching and (b) Template matching. The matching prediction mode is selected as one merge candidate (matching candidate) of the merge mode.

  The matching prediction unit 30373 derives a motion vector by matching regions in a plurality of reference images on the assumption that the object performs constant motion. In bilateral matching, matching between reference images A and B, assuming that an object passes through an area with a reference image A, a target PU with a target picture Cur_Pic, and a region with a reference image B with constant motion. The motion vector of the target PU is derived by In template matching, a motion vector is derived by matching the adjacent area Temp_Cur of the target PU with the adjacent area Temp_L0 of the reference block on the reference picture, on the assumption that the adjacent area of the target PU and the motion vector of the target PU are equal. The matching prediction unit divides the target PU into a plurality of subblocks, and performs bilateral matching or template matching described later on a divided subblock basis to obtain motion vectors spMvLX [xi] [yj] of the subblocks (xi = xPb + nSbW * i, yj = yPb + nSbH * j, i = 0, 1, 2, ..., nPbW / nSbW-1, j = 0, 1, 2, ..., nPbH / nSbH-1) Derive

As shown in (a) of FIG. 14, in bilateral matching, two reference images are referred to in order to derive a motion vector of a sub block Cur_block in a target picture Cur_Pic. More specifically, first, when the coordinates of the sub-block Cur_block are expressed as (xCur, yCur), it is an area in a reference image (referred to as a reference picture A) specified by the reference picture index Ref0
(XPos0, yPos0) = (xCur + MV0_x, yCur + MV0_y)
And an area in a reference image (referred to as a reference picture B) specified by a reference picture index Ref1 and Block_A having upper left coordinates (xPos0, yPos0) specified by
(XPos1, yPos1) = (xCur + MV1_x, xCur + MV1_y) = (xCur-MV0_x * TD1 / TD0, yCur-MV0_y * TD1 / TD0)
And Block_B having the upper left coordinates (xPos1, yPos1) specified by. Here, TD0 and TD1 represent the inter-picture distance between the target picture Cur_Pic and the reference picture A and the inter-picture distance between the target picture Cur_Pic and the reference picture B, respectively, as shown in FIG. ing.

  Next, (MV0_x, MV0_y) is determined such that the matching cost between Block_A and Block_B is minimized. The (MV0_x, MV0_y) derived in this manner is the motion vector assigned to the sub block.

  On the other hand, (b) of FIG. 14 is a figure for demonstrating template matching (Template matching) among the said matching processes.

  As shown in (b) of FIG. 14, in template matching, one reference picture is referred to in order to derive the motion vector of the sub block Cur_block in the target picture Cur_Pic.

More specifically, first, an area in a reference picture (referred to as reference picture A) specified by the reference picture index Ref0,
(XPos0, yPos0) = (xCur + MV0_x, yCur + MV0_y)
A reference block Block_A having the upper left coordinates (xPos0, yPos0) specified by is identified. Here, (xCur, yCur) is the upper left coordinates of the sub block Cur_block.

  Next, in the target picture Cur_Pic, a template region Temp_Cur adjacent to the sub block Cur_block and a template region Temp_L0 adjacent to the Block_A in the reference picture A are set. In the example shown in (b) of FIG. 14, the template region Temp_Cur is configured of a region adjacent to the upper side of the sub block Cur_block and a region adjacent to the left side of the sub block Cur_block. The template region Temp_L0 is configured of a region adjacent to the upper side of the Block_A and a region adjacent to the left side of the Block_A.

  Next, the matching cost between Temp_Cur and TempL0 is determined to be minimum (MV0_x, MV0_y), and the motion vector spMvLX to be assigned to the sub block is obtained.

  FIG. 7 is a schematic view showing the configuration of the merge prediction parameter derivation unit 3036 according to the present embodiment. The merge prediction parameter derivation unit 3036 includes a merge candidate derivation unit 30361, a merge candidate selection unit 30362, and a merge candidate storage unit 30363. The merge candidate storage unit 30363 stores the merge candidate input from the merge candidate derivation unit 30361. The merge candidate is configured to include a prediction list use flag predFlagLX, a motion vector mvLX, and a reference picture index refIdxLX. In the merge candidate storage unit 30363, an index is assigned to the stored merge candidate according to a predetermined rule.

  The merge candidate derivation unit 30361 derives merge candidates using the motion vector of the adjacent PU for which the decoding process has already been performed and the reference picture index refIdxLX as it is. Alternatively, merge candidates may be derived using affine prediction. This method is described in detail below. The merge candidate derivation unit 30361 may use affine prediction for spatial merge candidate derivation processing, temporal merge candidate derivation processing, combined merge candidate derivation processing, and zero merge candidate derivation processing described later. Affine prediction is performed in units of subblocks, and prediction parameters are stored in the prediction parameter memory 307 for each subblock. Alternatively, affine prediction may be performed pixel by pixel.

(Space merge candidate derivation process)
As the spatial merge candidate derivation process, the merge candidate derivation unit 30361 reads out and reads the prediction parameters (prediction list use flag predFlagLX, motion vector mvLX, reference picture index refIdxLX) stored in the prediction parameter memory 307 according to a predetermined rule The prediction parameters are derived as merge candidates. The prediction parameters to be read out are prediction parameters relating to each of the PUs within a predetermined range from the target PU (for example, all or part of PUs in contact with the lower left end, upper left end, and upper right end of the target PU). The merge candidate derived by the merge candidate derivation unit 30361 is stored in the merge candidate storage unit 30363.

(Time merge candidate derivation process)
As a time merge derivation process, the merge candidate derivation unit 30361 reads the prediction parameter of the PU in the reference image including the lower right coordinates of the target PU from the prediction parameter memory 307 as a merge candidate. The reference image may be specified, for example, by the reference picture index refIdxLX specified in the slice header, or by using the smallest reference picture index refIdxLX of the PU adjacent to the target PU. The merge candidate derived by the merge candidate derivation unit 30361 is stored in the merge candidate storage unit 30363.

(Joining merge candidate derivation process)
As the merge merge derivation process, the merge candidate derivation unit 30361 sets the motion vector and reference picture index of two different derived merge candidates that are already derived and stored in the merge candidate storage unit 30363 as L0 and L1 motion vectors, respectively. Combining merge candidates are derived. The merge candidate derived by the merge candidate derivation unit 30361 is stored in the merge candidate storage unit 30363.

(Zero merge candidate derivation process)
As the zero merge candidate derivation process, the merge candidate derivation unit 30361 derives a merge candidate in which the reference picture index refIdxLX is 0 and both the X component and the Y component of the motion vector mvLX are 0. The merge candidate derived by the merge candidate derivation unit 30361 is stored in the merge candidate storage unit 30363.

  Among the merge candidates stored in the merge candidate storage unit 30363, the merge candidate selection unit 30362 selects, as the target PU, the merge candidate to which the index corresponding to the merge index merge_idx input from the inter prediction parameter decoding control unit 3031 is assigned. Select as inter prediction parameter of. The merge candidate selection unit 30362 stores the selected merge candidate in the prediction parameter memory 307 and outputs the merge candidate to the predicted image generation unit 308.

  FIG. 8 is a schematic diagram showing the configuration of the AMVP prediction parameter derivation unit 3032 according to the present embodiment. The AMVP prediction parameter derivation unit 3032 includes a vector candidate derivation unit 3033, a vector candidate selection unit 3034, and a vector candidate storage unit 3035. The vector candidate derivation unit 3033 derives a prediction vector candidate from the already processed PU motion vector stored in the prediction parameter memory 307 based on the reference picture index refIdx, and the prediction vector candidate list mvpListLX [] of the vector candidate storage unit 3035 Store in

  The vector candidate selection unit 3034 selects a motion vector mvpListLX [mvp_LX_idx] indicated by the prediction vector index mvp_LX_idx among the prediction vector candidates of the prediction vector candidate list mvpListLX [] as a prediction vector mvpLX. The vector candidate selection unit 3034 outputs the selected prediction vector mvpLX to the addition unit 3035.

  The prediction vector candidate is a PU for which decoding processing has been completed, and is derived by scaling a motion vector of a PU (for example, an adjacent PU) in a predetermined range from the target PU. Note that the adjacent PU includes a PU spatially adjacent to the target PU, for example, a left PU, an upper PU, and an area temporally adjacent to the target PU, for example, the same position as the target PU, and the display time is different. It contains the region obtained from the prediction parameters of PU.

  The addition unit 3035 adds the prediction vector mvpLX input from the AMVP prediction parameter derivation unit 3032 and the difference vector mvdLX input from the inter prediction parameter decoding control unit 3031 to calculate a motion vector mvLX. The addition unit 3035 outputs the calculated motion vector mvLX to the predicted image generation unit 308 and the prediction parameter memory 307.

(Inter predicted image generation unit 309)
FIG. 11 is a schematic diagram showing a configuration of the inter predicted image generation unit 309 included in the predicted image generation unit 308 according to the present embodiment. The inter predicted image generation unit 309 includes a motion compensation unit (predicted image generation device) 3091 and a weight prediction unit 3094.

(Motion compensation)
The motion compensation unit 3091 generates a reference picture index refIdxLX from the reference picture memory 306 based on the inter prediction parameters (prediction list use flag predFlagLX, reference picture index refIdxLX, motion vector mvLX) input from the inter prediction parameter decoding unit 303. In the reference picture specified in, the interpolation image (motion compensation image) is generated by reading out the block located at a position shifted by the motion vector mvLX from the position of the target PU. Here, when the accuracy of the motion vector mvLX is not integer accuracy, a filter called a motion compensation filter for generating pixels at decimal positions is applied to generate a motion compensated image.

(Weight prediction)
The weight prediction unit 3094 generates a predicted image of PU by multiplying the input motion compensated image predSamplesLX by a weighting factor. If one of the prediction list use flags (predFlagL0 or predFlagL1) is 1 (in the case of uni-prediction), and if weight prediction is not used, input motion compensated image predSamplesLX (LX is L0 or L1) with pixel bit number bitDepth Perform the processing of the following formula according to.

predSamples [X] [Y] = Clip3 (0, (1 << bitDepth)-1, (predSamplesLX [X] [Y] + offset1) >> shift1)
Here, shift1 = 14−bitDepth, offset1 = 1 << (shift1-1).
Also, when both of the reference list use flags (predFlagL0 and predFlagL1) are 1 (in the case of bi-predictive BiPred), and weight prediction is not used, the input motion compensated images predSamplesL0 and predSamplesL1 are averaged and the number of pixel bits Perform the processing of the following formula according to.

predSamples [X] [Y] = Clip3 (0, (1 << bitDepth)-1, (predSamplesL0 [X] [Y] + predSamplesL1 [X] [Y] + offset2) >> shift2)
Here, shift2 = 15-bit Depth, offset2 = 1 << (shift2-1).

  Furthermore, in the case of single prediction, in the case of performing weight prediction, the weight prediction unit 3094 derives the weight prediction coefficient w0 and the offset o0 from the encoded data, and performs the processing of the following equation.

predSamples [X] [Y] = Clip3 (0, (1 << bitDepth)-1, ((predSamplesLX [X] [Y] * w0 + 2 ^ (log2WD-1) >> log2WD) + o0)
Here, log2WD is a variable indicating a predetermined shift amount.

  Furthermore, in the case of bi-prediction BiPred, in the case of performing weight prediction, the weight prediction unit 3094 derives weight prediction coefficients w0, w1, o0, and o1 from encoded data, and performs the processing of the following formula.

predSamples [X] [Y] = Clip 3 (0, (1 << bitDepth)-1, (predSamplesL0 [X] [Y] * w0 + predSamplesL1 [X] [Y] * w1 + ((o0 + o1 + 1) << log 2 WD)) >> (log 2 WD + 1))
<Motion vector decoding process>
The motion vector decoding process according to the present embodiment will be specifically described below with reference to FIG.

  As apparent from the above description, in the motion vector decoding process according to the present embodiment, a process of decoding syntax elements related to inter prediction (also referred to as motion syntax decoding process) and a process of deriving a motion vector ( Motion vector derivation processing).

(Motion syntax decoding process)
FIG. 9 is a flowchart showing a flow of inter prediction syntax decoding processing performed by the inter prediction parameter decoding control unit 3031. In the following description of the description of FIG. 9, each processing is performed by the inter prediction parameter decoding control unit 3031 unless otherwise specified.

First, in step S101, merge flag merge_flag is decoded, and in step S102,
merge_flag! = 0 (whether merge_flag is not 0)
Is judged.

  If merge_flag! = 0 is true (Y in S102), the merge index merge_idx is decoded in S103, and motion vector derivation processing in merge mode (S111) is performed.

  If merge_flag! = 0 is false (N in S102), the inter prediction identifier inter_pred_idc is decoded in S104.

  When inter_pred_idc is other than PRED_L1 (PRED_L0 or PRED_BI), the reference picture index refIdxL0, the difference vector parameter mvdL0, and the prediction vector index mvp_L0_idx are respectively decoded in S105, S106, and S107.

  When inter_pred_idc is other than PRED_L0 (PRED_L1 or PRED_BI), in S108, S109, and S110, the reference picture index refIdxL1, the difference vector parameter mvdL1, and the prediction vector index mvp_L1_idx are decoded. Subsequently, motion vector derivation processing (S112) in the AMVP mode is executed.

(Effect of image decoding device)
In the image decoding device 31 according to the present embodiment, the affine prediction unit 30372 performs either 4-parameter affine or 6-parameter affine processing based on the shape and / or size of the target PU. Therefore, highly reliable affine parameters can be derived. In addition, it is possible to reduce the amount of code in the case of explicitly encoding affine parameters.

Second Embodiment
Hereinafter, a second embodiment of the present invention will be described. In the first embodiment, the inter prediction parameter decoding unit 303 determines which of the four-parameter affine and the six-parameter affine to perform based on the shape, size, and the like of the target PU. In the present embodiment, the inter prediction parameter decoding unit 303 determines which of the four parameter affine and the six parameter affine based on the shape or size of the block (adjacent block, merge reference block in the case of merge, etc.) adjacent to the target PU. Decide whether to process. The configuration of the inter prediction parameter decoding unit 303 is the same as that described in the first embodiment, and thus will not be described again.

  FIG. 28 is a flowchart showing an example of processing in which the inter prediction parameter decoding unit 303 determines which of the four parameter affine and the six parameter affine to perform based on the shape of the adjacent block. In the example shown in FIG. 28, in the inter prediction parameter decoding unit 303, the inter prediction parameter decoding control unit 3031 first determines whether the width (neighWidth) and height (neighHeight) of the adjacent block are equal (SH1). In FIG. 28 and FIG. 29 described later, neighWidth and neighHeight are described as width and height, respectively.

  If the width and height of the adjacent block are equal (Y in SH1), the affine prediction unit 30372 (or the AMVP prediction parameter decoding unit 3032) performs 6-parameter affine processing (SH2). If the width of the target PU and the height of the target PU are not equal (N in SH1), the affine prediction unit 30372 (or the AMVP prediction parameter decoding unit 3032) performs 4-parameter affine processing (SH3).

(Determined by the shape of the merge reference block)
FIG. 29 is a diagram for describing an example of selection of the number of control points by the process shown in FIG. In FIG. 29, PU indicates a target PU, and RB indicates an adjacent block.

  In the example shown in FIG. 29A, the width and height of the adjacent block are not equal. Therefore, the affine prediction unit 30372 refers to two motion vectors (for example, v2 and v3) on the adjacent block, derives motion vectors for two control points (for example, V1 and V2) on the target block, and processes the four parameter affine. Run.

  In the example shown in (b) of FIG. 29, the width and height of the adjacent block are not equal. Therefore, the affine prediction unit 30372 refers to two motion vectors (for example, v1 and v3) on the adjacent block, derives motion vectors for two control points (for example, V1 and V2) on the target block, and processes the four parameter affine. Run.

  In the example shown in (c) of FIG. 29, the width and height of the adjacent block are equal. Therefore, the affine prediction unit 30372 derives motion vectors of three control points (for example, V0, V1 and V2) on the target block by referring to three motion vectors (for example, v1, v2 and v3) on adjacent blocks. Perform parameter affine processing.

  In the example shown in (d) of FIG. 29, the width and height of the adjacent block are equal. Therefore, the affine prediction unit 30372 derives motion vectors of three control points (for example, V0, V1 and V2) on the target block by referring to three motion vectors (for example, v0, v1 and v2) on adjacent blocks. Perform parameter affine processing.

  In the description of (a) to (d) in FIG. 29, the affine prediction unit 30372 performs the processing of four parameter affine or six parameter affine, but the AMVP prediction parameter decoding unit 3032 performs four parameter affine or six parameter Affine processing may be performed.

(Determined by the size of the merge reference block)
FIG. 30 is a flowchart showing an example of processing in which the inter prediction parameter decoding unit 303 determines which of the four parameter affine and the six parameter affine to perform based on the size of the adjacent block. In the example illustrated in FIG. 30, first, the inter prediction parameter decoding control unit 3031 determines whether the value indicating the size of the adjacent block is equal to or larger than a predetermined threshold (SI1). If the value indicating the size of the adjacent block is equal to or larger than the predetermined threshold (Y in SI1), the affine prediction unit 30372 (or the AMVP prediction parameter decoding unit 3032) performs six parameter affine processing (SI2). If the value indicating the size of the adjacent block is not equal to or larger than the predetermined threshold (N in SI1), the affine prediction unit 30372 (or the AMVP prediction parameter decoding unit 3032) performs 4-parameter affine processing (SI3).

  FIG. 31 is a diagram for describing an example of selection of the number of control points by the process shown in FIG. In FIG. 31, PU indicates a target PU, and RB indicates an adjacent block. In the following description, log2 (neighWidth) + log2 (neighHeight) is used as a value indicating the size of the adjacent block.

  (A) and (b) of FIG. 31 show an example in which the size of the adjacent block is smaller than the predetermined threshold TH, and in (c) and (d) of FIG. An example is shown. In the example of FIG. 31, the size of the target block is 8 × 8 (log 2 (pu Width) + log 2 (puHeight) = 6), (a), (b), (c), and (d)). Although an example in which 4 × 4, 4 × 4, 8 × 8, 4 × 8, and TH = 5 are shown, the sizes and thresholds of the target block and the reference block are not limited thereto.

  In the example shown in FIG. 31 (a), the size of the adjacent block is smaller than a predetermined threshold TH (log 2 (neighWidth) + log 2 (neighHeight) <TH). Therefore, the affine prediction unit 30372 refers to two motion vectors (for example, v2 and v3) on the adjacent block, derives motion vectors for two control points (for example, V1 and V2) on the target block, and processes the four parameter affine. Run.

  In the example illustrated in (b) of FIG. 31, the size of the adjacent block is smaller than a predetermined threshold TH (log 2 (neighWidth) + log 2 (neighHeight) <TH). Therefore, the affine prediction unit 30372 refers to two motion vectors (for example, v1 and v3) on the adjacent block, derives motion vectors for two control points (for example, V1 and V2) on the target block, and processes the four parameter affine. Run.

  In the example illustrated in (c) of FIG. 31, the size of the adjacent block is equal to or larger than a predetermined threshold TH (log 2 (neighWidth) + log 2 (neighHeight)> = TH). Therefore, the affine prediction unit 30372 derives motion vectors of three control points (for example, V0, V1 and V2) on the target block by referring to three motion vectors (for example, v1, v2 and v3) on adjacent blocks. Perform parameter affine processing.

  In the example illustrated in (d) of FIG. 31, the size of the adjacent block is equal to or larger than a predetermined threshold TH (log 2 (neighWidth) + log 2 (neighHeight)> = TH). Therefore, the affine prediction unit 30372 derives motion vectors of three control points (for example, V0, V1 and V2) on the target block by referring to three motion vectors (for example, v0, v1 and v3) on adjacent blocks. Perform parameter affine processing.

In addition, as a value which shows the size of object PU, the following can be used, for example.
・ Max (neighWidth, neighHeight)
・ Min (neighWidth, neighHeight)
・ NeighWidth + neighHeight
・ NeighWidth * neighHeight
・ Log 2 (neighWidth) + log 2 (neighHeight)
However, the value indicating the size of the target PU is not limited to the above example.

Also, the determination on the size of the adjacent block may be as follows.
Whether the size of the target PU is larger than a predetermined threshold value.
• Whether the size of the target PU is less than or equal to a predetermined threshold value.
• Whether the size of the target PU is smaller than a predetermined threshold.

(Effect of image decoding device)
In the image decoding device 31 according to the present embodiment, the affine prediction unit 30372 performs either 4-parameter affine or 6-parameter affine processing based on the shape or size of the adjacent block. Such an inter prediction parameter decoding unit 303 can also derive highly reliable affine parameters. In addition, it is possible to reduce the amount of code in the case of explicitly encoding affine parameters.

Third Embodiment
Hereinafter, a third embodiment of the present invention will be described. In the first embodiment, the inter prediction parameter decoding unit 303 determines which of the four-parameter affine and the six-parameter affine to perform based on the shape, size, and the like of the target PU. This embodiment relates to the selection of control points in a four parameter affine. In the present embodiment, the inter prediction parameter decoding unit 303 may switch any of the four parameter affine and six parameter affine processes, or may always perform the four parameter affine process. The inter prediction parameter decoding unit 303 of the present embodiment determines the position of the control point for deriving the motion vector used for the four parameter affine, based on the shape of the target PU.

  FIG. 32 is a flowchart of processing in which the inter prediction parameter decoding unit 303 determines the position of a control point for deriving a motion vector based on the shape of a target PU. In the example shown in FIG. 32, in the inter prediction parameter decoding unit 303, the inter prediction parameter decoding control unit 3031 first determines whether the target PU is a square (SJ1). If the target PU is a square (Y in SJ1), the inter prediction parameter decoding control unit 3031 sets two vertices on the diagonal of the target PU as control points (SJ2). If the target PU is not a square (N in SJ1), the inter prediction parameter decoding control unit 3031 sets two vertices sandwiching the long side of the target PU as control points (SJ3). Thereafter, the affine prediction unit 30372 (or the AMVP prediction parameter decoding unit 3032) performs 4-parameter affine processing with the selected control point (SJ4).

  FIG. 33 is a diagram illustrating an example of the positions of control points determined by the inter prediction parameter decoding unit 303 according to the present embodiment. As shown in (a) of FIG. 33, when the shape of the target PU is a square, the inter prediction parameter decoding unit 303 sets two vertices (for example, control points V1 and V2) on the diagonal of the target PU to four. Determined as a control point to be used for parameter affine processing.

  As shown in (b) and (c) of FIG. 33, when the shape of the target PU is not a square, the inter prediction parameter decoding unit 303 processes the two vertices sandwiching the long side of the target PU into a four-parameter affine process. Determined as the control point to be used. Specifically, for example, in the example shown in (b) of FIG. 33, the inter prediction parameter decoding unit 303 derives motion vectors of the control points V0 and V2, and uses the motion vectors for four parameter affine. Further, for example, in the example illustrated in (c) of FIG. 33, the inter prediction parameter decoding unit 303 derives motion vectors of control points V0 and V1, and uses the motion vectors for four-parameter affine.

  The inter prediction parameter decoding unit 303 of the present embodiment determines the position of the control point according to the shape of the target PU. Therefore, the accuracy of the motion vector used by the inter prediction parameter decoding unit 303 for the four parameter affine is improved.

  In the above example, the inter prediction parameter decoding unit 303 switches the control point to be referred to in the three patterns in the case where the shape of the target PU is a square, a horizontally long rectangle, or a vertically long rectangle. Alternatively, the control points may be switched in two patterns. For example, the inter prediction parameter decoding unit 303 determines the control points V0 and V1 as control points when the shape of the target PU is puWidth> = puHeight, and controls points V0 and V2 otherwise (puWidth <puHeight). As the control point. Also, the following configuration may be used. The inter prediction parameter decoding unit 303 determines the control points V0 and V1 as control points when the shape of the target PU is puWidth> puHeight, and otherwise controls the control points V0 and V2 (puWidth <= puHeight). Determined as a point.

Fourth Embodiment
Hereinafter, a fourth embodiment of the present invention will be described. In the second embodiment, the inter prediction parameter decoding unit 303 determines which of the four-parameter affine and the six-parameter affine to perform based on the shape or the size of the adjacent block. This embodiment relates to the selection of control points in a four parameter affine. In the present embodiment, the inter prediction parameter decoding unit 303 may switch any of the four parameter affine and six parameter affine processes, or may always perform the four parameter affine process. At this time, the inter prediction parameter decoding unit 303 changes the control point used for the four parameter affine processing according to the shape of the adjacent block. Specifically, the inter prediction parameter decoding unit 303 determines, based on the shape of the adjacent block, the position of the control point in the adjacent block that derives the motion vector used for the four parameter affine.

  FIG. 34 is a flowchart of processing in which the inter prediction parameter decoding unit 303 determines the position of the point of the adjacent block used to derive the motion vector of the control point based on the shape of the adjacent block. In the example shown in FIG. 34, in the inter prediction parameter decoding unit 303, the inter prediction parameter decoding control unit 3031 first determines whether the adjacent block is a square (SK1). If the adjacent block is a square (Y in SK1), the inter prediction parameter decoding control unit 3031 determines two points on the diagonal of the adjacent block to be used for deriving the motion vector of the control point (SK2). If the adjacent block is not a square (N in SK1), the inter prediction parameter decoding control unit 3031 determines the points used for deriving the motion vector of the control point to be two points across the long side of the adjacent block (SK3). Thereafter, the affine prediction unit 30372 (or the AMVP prediction parameter decoding unit 3032) derives the motion vector of the control point using the point of the selected adjacent block, and performs 4-parameter affine processing (SK4).

  FIG. 35 is a diagram illustrating an example of the positions of control points determined by the inter prediction parameter decoding unit 303 according to the present embodiment. As shown in (a) and (b) of FIG. 35, when the shape of the adjacent block is a square, the inter prediction parameter decoding unit 303 sets two vertices on the diagonal of the adjacent block (for example, positions at the upper left of the adjacent block) The motion vector of two control points (for example, V1 and V2) on the target block is derived with reference to the motion vector of the point v0 and the point v3 located at the lower right, and the processing of four parameter affine is executed.

  As shown in (c) to (f) of FIG. 35, when the shape of the adjacent block is rectangular, the inter prediction parameter decoding unit 303 refers to the motion vector of the two vertices sandwiching the long side of the adjacent block. Then, motion vectors of two control points (for example, V1 and V2) on the target block are derived, and a four-parameter affine process is performed. For example, as shown in (c) and (d) of FIG. 35, when the shape of the adjacent block is a rectangle longer in the height direction than in the width direction, the inter prediction parameter decoding unit 303 determines whether the adjacent block has a height in the height direction. The motion vectors of two points located at both ends of the side (for example, point v1 located at the upper right of the adjacent block and point v3 located at the lower right) are used. For example, as shown in (e) and (f) of FIG. 35, when the shape of the adjacent block is a rectangle longer in the width direction than in the height direction, the inter prediction parameter decoding unit 303 determines the side in the width direction of the adjacent block. The motion vectors of two points located at both ends of (for example, point v2 located at the lower left of the adjacent block and point v3 located at the lower right) are used.

  The inter prediction parameter decoding unit 303 of the present embodiment determines the position of the vertex in the adjacent block used to derive the motion vectors of the two control points on the target block according to the shape of the adjacent block. Such an inter prediction parameter decoding unit 303 also improves the accuracy of the motion vector used by the inter prediction parameter decoding unit 303 for the four parameter affine.

Fifth Embodiment
Hereinafter, a fifth embodiment of the present invention will be described. In the fourth embodiment, the inter prediction parameter decoding unit 303 determines the position of the vertex in the adjacent block used to derive the motion vectors of the two control points on the target block based on the shape of the adjacent block. In the present embodiment, the inter prediction parameter decoding unit 303 determines the position of the control point in the target PU based on the shape of the adjacent block.

  FIG. 36 is a flowchart of processing in which the inter prediction parameter decoding unit 303 determines the position of the control point from which the motion vector is derived based on the shape of the adjacent block. In the example shown in FIG. 36, in the inter prediction parameter decoding unit 303, the inter prediction parameter decoding control unit 3031 first determines whether the adjacent block is a square (SL1). If the adjacent block is a square (Y in SL1), the inter prediction parameter decoding control unit 3031 sets two vertices on the diagonal of the target PU as control points (SL2). If the adjacent block is not a square (N in SL1), the inter prediction parameter decoding control unit 3031 sets two vertices sandwiching the side of the target PU adjacent to the adjacent block as control points (SL3). Thereafter, the affine prediction unit 30372 (or the AMVP prediction parameter decoding unit 3032) performs 4-parameter affine processing with the selected control point (SL4).

  FIG. 37 is a diagram illustrating an example of the positions of control points determined by the inter prediction parameter decoding unit 303 according to the present embodiment. As shown in (a) and (b) of FIG. 37, when the shape of the adjacent block is a square, the inter prediction parameter decoding unit 303 sets two vertices (for example, V0 and V3) on the diagonal of the target PU, Determined as the control point used for 4-parameter affine.

  If the shape of the adjacent block is rectangular as shown in (c) to (f) of FIG. 37, the inter prediction parameter decoding unit 303 sets two vertices that sandwich the side of the target PU in contact with the adjacent block. , And determined as control points to be used for 4-parameter affine. For example, as shown in (c) and (e) of FIG. 37, when the adjacent block is in contact with the left side of the target PU, the inter prediction parameter decoding unit 303 determines the side of the target PU in contact with the adjacent block. Two points located at both ends of (the point V1 located at the upper left of the object PU and the point V3 located at the lower left) are taken as control points. For example, as shown in (d) or (f) of FIG. 37, when the adjacent block is in contact with the upper side of the target PU, the inter prediction parameter decoding unit 303 determines the side of the target PU in contact with the adjacent block. Let two points (point V0 located at the upper left of the object PU and point V1 located at the upper right) located at both ends of the control point be control points.

  The inter prediction parameter decoding unit 303 of the present embodiment determines the position of the control point in the adjacent block according to the shape of the adjacent block. Such an inter prediction parameter decoding unit 303 also improves the accuracy of the motion vector used by the inter prediction parameter decoding unit 303 for the four parameter affine.

(Configuration of image coding apparatus)
Next, the configuration of the image encoding device 11 (moving image encoding device) according to the present embodiment will be described. FIG. 4 is a block diagram showing the configuration of the image coding apparatus 11 according to the present embodiment. The image coding device 11 includes a predicted image generation unit 101, a subtraction unit 102, a DCT / quantization unit 103, an entropy coding unit 104, an inverse quantization / inverse DCT unit 105, an addition unit 106, a loop filter 107, 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, and prediction parameter coding unit 111 are configured. The prediction parameter coding unit 111 includes an inter prediction parameter coding unit 112 (a prediction image generation device) and an intra prediction parameter coding unit 113.

  The prediction image generation unit 101 generates, for each picture of the image T, the prediction image P of the prediction unit PU for each coding unit CU, which is an area obtained by dividing the picture. Here, the predicted image generation unit 101 reads a decoded block from the reference picture memory 109 based on the prediction parameter input from the prediction parameter coding unit 111. The prediction parameter input from the prediction parameter coding unit 111 is, for example, a motion vector in the case of inter prediction. The predicted image generation unit 101 reads a block at a position on the reference image indicated by the motion vector starting from the target PU. In the case of intra prediction, the prediction parameter is, for example, an intra prediction mode. The pixel value of the adjacent PU used in the intra prediction mode is read from the reference picture memory 109, and a PU predicted image P is generated. The prediction image generation unit 101 generates a PU prediction image P using one of a plurality of prediction methods for the read reference picture block. The prediction image generation unit 101 outputs the generated prediction image P of PU to the subtraction unit 102.

  The predicted image generation unit 101 performs the same operation as the predicted image generation unit 308 described above. For example, FIG. 6 is a schematic diagram showing a configuration of the inter predicted image generation unit 1011 included in the predicted image generation unit 101. The inter prediction image generation unit 1011 includes a motion compensation unit 10111 and a weight prediction unit 10112. The motion compensation unit 10111 and the weight prediction unit 10112 have the same configuration as that of the above-described motion compensation unit 3091 and weight prediction unit 3094, and therefore the description thereof is omitted here.

  The prediction image generation unit 101 generates a PU prediction image P based on the pixel value of the reference block read from the reference picture memory, using the parameter input from the prediction parameter coding unit. The predicted image generated by the predicted image generation unit 101 is output to the subtraction unit 102 and the addition unit 106.

  The subtraction unit 102 subtracts the signal value of the predicted image P of the PU input from the predicted image generation unit 101 from the pixel value of the corresponding PU of the image T to generate a residual signal. The subtraction unit 102 outputs the generated residual signal to the DCT / quantization unit 103.

  The DCT / quantization unit 103 performs DCT on the residual signal input from the subtraction unit 102 to calculate DCT coefficients. The DCT / quantization unit 103 quantizes the calculated DCT coefficient to obtain a quantization coefficient. The DCT / quantization unit 103 outputs the obtained quantization coefficient to the entropy coding unit 104 and the inverse quantization / inverse DCT unit 105.

  The entropy coding unit 104 receives the quantization coefficient from the DCT / quantization unit 103, and receives the coding parameter from the prediction parameter coding unit 111. The coding parameters to be input include, for example, codes such as a reference picture index refIdxLX, a prediction vector index mvp_LX_idx, a difference vector mvdLX, a prediction mode predMode, and a merge index merge_idx.

  The entropy coding unit 104 entropy-codes the input quantization coefficient and coding parameters to generate a coded stream Te, and outputs the generated coded stream Te to the outside.

  The inverse quantization / inverse DCT unit 105 inversely quantizes the quantization coefficient input from the DCT / quantization unit 103 to obtain a DCT coefficient. The inverse quantization / inverse DCT unit 105 performs inverse DCT on the obtained DCT coefficients to calculate a residual signal. The inverse quantization / inverse DCT unit 105 outputs the calculated residual signal to the addition unit 106.

  The addition unit 106 adds, for each pixel, the signal value of the predicted image P of the PU input from the prediction image generation unit 101 and the signal value of the residual signal input from the inverse quantization / inverse DCT unit 105 for decoding. Generate an image. The addition unit 106 stores the generated decoded image in the reference picture memory 109.

  The loop filter 107 applies a deblocking filter, a sample adaptive offset (SAO), and an adaptive loop filter (ALF) to the decoded image generated by the adding unit 106.

  The prediction parameter memory 108 stores the prediction parameter generated by the coding parameter determination unit 110 in a predetermined position for each picture and CU to be coded.

  The reference picture memory 109 stores the decoded image generated by the loop filter 107 in a predetermined position for each picture and CU to be encoded.

  The coding parameter determination unit 110 selects one of a plurality of sets of coding parameters. The coding parameter is a prediction parameter described above or a parameter to be coded that is generated in association with the prediction parameter. The prediction image generation unit 101 generates a PU prediction image P using each of these sets of coding parameters.

  The coding parameter determination unit 110 calculates, for each of the plurality of sets, a cost value indicating the size of the information amount and the coding error. The cost value is, for example, the sum of the code amount and a value obtained by multiplying the square error by the coefficient λ. The code amount is the information amount of the coded stream Te obtained by entropy coding the quantization error and the coding parameter. The squared error is a sum between pixels with respect to the square value of the residual value of the residual signal calculated by the subtraction unit 102. The factor λ is a real number greater than a preset zero. The coding parameter determination unit 110 selects a set of coding parameters that minimize the calculated cost value. Thereby, the entropy coding unit 104 externally outputs the set of selected coding parameters as the coded stream Te, and does not output the set of non-selected coding parameters. The coding parameter determination unit 110 stores the determined coding parameters in the prediction parameter memory 108.

  The prediction parameter coding unit 111 derives a format for coding from the parameters input from the coding parameter determination unit 110, and outputs the format to the entropy coding unit 104. Derivation of a form for encoding is, for example, derivation of a difference vector from a motion vector and a prediction vector. Further, the prediction parameter coding unit 111 derives parameters necessary to generate a prediction image from the parameters input from the coding parameter determination unit 110, and outputs the parameters to the prediction image generation unit 101. The parameters required to generate a predicted image are, for example, motion vectors in units of subblocks.

  The inter prediction parameter coding unit 112 derives inter prediction parameters such as a difference vector based on the prediction parameters input from the coding parameter determination unit 110. The inter prediction parameter coding unit 112 derives the inter prediction parameter by the inter prediction parameter decoding unit 303 (refer to FIG. 5 and the like) as a configuration for deriving the parameters necessary for generating the prediction image to be output to the prediction image generation unit 101. Partially include the same configuration as the configuration. The configuration of the inter prediction parameter coding unit 112 will be described later.

  The intra prediction parameter coding unit 113 derives a format (for example, MPM_idx, rem_intra_luma_pred_mode, etc.) for coding from the intra prediction mode IntraPredMode input from the coding parameter determination unit 110.

(Configuration of inter prediction parameter coding unit)
Next, the configuration of the inter prediction parameter coding unit 112 will be described. The inter prediction parameter coding unit 112 is a means corresponding to the inter prediction parameter decoding unit 303 in FIG. 12, and the configuration is shown in FIG.

  The inter prediction parameter coding unit 112 includes an inter prediction parameter coding control unit 1121, an AMVP prediction parameter derivation unit 1122 (affine motion vector derivation unit, affine motion vector derivation device), a subtraction unit 1123, a sub block prediction parameter derivation unit 1125, And a division mode derivation unit, a merge flag derivation unit, an inter prediction identifier derivation unit, a reference picture index derivation unit, a vector difference derivation unit, etc. not shown, and a division mode derivation unit, a merge flag derivation unit, an inter prediction identifier The derivation unit, the reference picture index derivation unit, and the vector difference derivation unit respectively derive a PU division mode part_mode, a merge flag merge_flag, an inter prediction identifier inter_pred_idc, a reference picture index refIdxLX, and a difference vector mvdLX. The inter prediction parameter coding unit 112 outputs the motion vector (mvLX, subMvLX), the reference picture index refIdxLX, the PU division mode part_mode, the inter prediction identifier inter_pred_idc, or information indicating these to the predicted image generation unit 101. In addition, the inter prediction parameter encoding unit 112 includes: PU division mode part_mode, merge flag merge_flag, merge index merge_idx, inter prediction identifier inter_pred_idc, reference picture index refIdxLX, prediction vector index mvp_LX_idx, difference vector mvdLX, sub block prediction mode flag subPbMotionFlag Output to encoding section 104.

  The inter prediction parameter coding control unit 1121 includes a merge index derivation unit 11211 and a vector candidate index derivation unit 11212. The merge index derivation unit 11211 compares the motion vector and reference picture index input from the coding parameter determination unit 110 with the motion vector and reference picture index of the PU of the merge candidate read from the prediction parameter memory 108, and merges The index merge_idx is derived and output to the entropy coding unit 104. The merge candidate is a reference PU in a predetermined range from the encoding target CU to be encoded (for example, a reference PU in contact with the lower left end, upper left end, upper right end of the encoding target block) It is PU which processing completed. The vector candidate index deriving unit 11212 derives a predicted vector index mvp_LX_idx.

  In the sub-block prediction parameter derivation unit 1125, when the coding parameter determination unit 110 determines to use the sub-block prediction mode, any of spatial sub-block prediction, temporal sub-block prediction, affine prediction and matching prediction according to the value of subPbMotionFlag The motion vector and reference picture index of some subblock prediction are derived. The motion vector and the reference picture index are derived from the prediction parameter memory 108 by reading out motion vectors and reference picture indexes such as adjacent PUs and reference picture blocks as described in the description of the image decoding apparatus. Specifically, the sub-block prediction parameter derivation unit 1125 has a configuration similar to that of the above-described sub-block prediction parameter derivation unit 3037 (see FIG. 12).

  The AMVP prediction parameter derivation unit 1122 has a configuration similar to that of the above-described AMVP prediction parameter derivation unit 3032 (see FIG. 12).

  That is, when the prediction mode predMode indicates the inter prediction mode, the motion vector mvLX is input from the coding parameter determination unit 110 to the AMVP prediction parameter derivation unit 1122. The AMVP prediction parameter derivation unit 1122 derives a prediction vector mvpLX based on the input motion vector mvLX. The AMVP prediction parameter derivation unit 1122 outputs the derived prediction vector mvpLX to the subtraction unit 1123. The reference picture index refIdx and the prediction vector index mvp_LX_idx are output to the entropy coding unit 104.

  The subtracting unit 1123 subtracts the prediction vector mvpLX input from the AMVP prediction parameter derivation unit 1122 from the motion vector mvLX input from the coding parameter determination unit 110 to generate a difference vector mvdLX. The difference vector mvdLX is output to the entropy coding unit 104.

  Note that the image encoding device 11 and a part of the image decoding device 31 in the embodiment described above, for example, the entropy decoding unit 301, the prediction parameter decoding unit 302, the loop filter 305, the prediction image generation unit 308, the inverse quantization / inverse DCT Unit 311, addition unit 312, predicted image generation unit 101, subtraction unit 102, DCT / quantization unit 103, entropy coding unit 104, inverse quantization / inverse DCT unit 105, loop filter 107, coding parameter determination unit 110, The prediction parameter coding unit 111 may be realized by a computer. In that case, a program for realizing the control function may be recorded in a computer readable recording medium, and the computer system may read and execute the program recorded in the recording medium. Here, the “computer system” is a computer system built in any of the image encoding device 11 and the image decoding device 31, and includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” means a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in a computer system. Furthermore, the “computer-readable recording medium” is one that holds a program dynamically for a short time, like a communication line in the case of transmitting a program via a network such as the Internet or a communication line such as a telephone line. In such a case, a volatile memory in a computer system serving as a server or a client may be included, which holds a program for a predetermined time. The program may be for realizing a part of the functions described above, or may be realized in combination with the program already recorded in the computer system.

  In addition, part or all of the image encoding device 11 and the image decoding device 31 in the above-described embodiment may be realized as an integrated circuit such as a large scale integration (LSI). Each functional block of the image encoding device 11 and the image decoding device 31 may be individually processorized, or part or all may be integrated and processorized. Further, the method of circuit integration is not limited to LSI's, and implementation using dedicated circuitry or general purpose processors is also possible. In the case where an integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology, integrated circuits based on such technology may also be used.

  As mentioned above, although one embodiment of this invention was described in detail with reference to drawings, a specific structure is not restricted to the above-mentioned thing, Various design changes etc. in the range which does not deviate from the summary of this invention It is possible to

[Application example]
The image encoding device 11 and the image decoding device 31 described above can be mounted and used in various devices that transmit, receive, record, and reproduce 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, the fact that the image encoding device 11 and the image decoding device 31 described above can be used for transmission and reception of a moving image will be described with reference to FIG.

  (A) of FIG. 38 is a block diagram showing a configuration of a transmission device PROD_A on which the image coding device 11 is mounted. As shown in (a) of FIG. 38, the transmission device PROD_A modulates a carrier wave with the coding unit PROD_A1 for obtaining coded data by coding a moving image, and the coding data obtained by the coding unit PROD_A1. A modulation unit PROD_A2 for obtaining a modulation signal thereby, and a transmission unit PROD_A3 for transmitting the modulation signal obtained by the modulation unit PROD_A2. The image coding apparatus 11 described above is used as the coding unit PROD_A1.

  The transmission device PROD_A is a camera PROD_A4 for capturing a moving image, a recording medium PROD_A5 for recording the moving image, an input terminal PROD_A6 for externally inputting the moving image, and a transmission source of the moving image input to the encoding unit PROD_A1 , And may further include an image processing unit A7 that generates or processes an image. Although (a) of FIG. 38 exemplifies a configuration in which the transmission device PROD_A includes all of these, a part may be omitted.

  Note that the recording medium PROD_A5 may be a recording of a non-coded moving image, or a moving image encoded by a recording encoding method different from the transmission encoding method. It may be one. In the latter case, it is preferable to interpose, between the recording medium PROD_A5 and the encoding unit PROD_A1, a decoding unit (not shown) that decodes the encoded data read from the recording medium PROD_A5 according to the encoding scheme for recording.

  (B) of FIG. 38 is a block diagram showing a configuration of a reception device PROD_B equipped with the image decoding device 31. As shown in FIG. As shown in (b) of FIG. 38, the receiver PROD_B receives the modulated signal, receives the modulated signal, demodulates the modulated signal received by the receiver PROD_B1, obtains the encoded data by the demodulated unit PROD_B2, and demodulates the received signal. And a decoding unit PROD_B3 for obtaining a moving image by decoding encoded data obtained by the unit PROD_B2. The 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 a 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 further comprise PROD_B6. Although (b) of FIG. 38 exemplifies a configuration in which the reception device PROD_B includes all of these, a part may be omitted.

  Incidentally, the recording medium PROD_B5 may be for recording a moving image which has not been encoded, or is encoded by a recording encoding method different from the transmission encoding method. May be In the latter case, an encoding unit (not shown) may be interposed between the decoding unit PROD_B3 and the recording medium PROD_B5 to encode the moving image acquired from the decoding unit PROD_B3 according to the encoding method for recording.

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

  For example, a broadcasting station (broadcasting facility etc.) / Receiving station (television receiver etc.) of terrestrial digital broadcasting is an example of a transmitting device PROD_A / receiving device PROD_B which transmits and receives a modulated signal by wireless broadcasting. A cable television broadcast station (broadcasting facility or the like) / receiving station (television receiver or the like) is an example of a transmitting device PROD_A / receiving device PROD_B which transmits and receives a modulated signal by cable broadcasting.

  In addition, a server (such as a workstation) / client (television receiver, personal computer, smart phone, etc.) such as a VOD (Video On Demand) service or a video sharing service using the Internet is a transmitting device that transmits and receives modulated signals by communication. This is an example of PROD_A / receiving device PROD_B (Normally, in a LAN, either wireless or wired is used as a transmission medium, and in WAN, wired is used as a transmission medium). Here, the personal computer includes a desktop PC, a laptop PC, and a tablet PC. The smartphone also includes a multifunctional mobile phone terminal.

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

  Next, the fact that the image encoding device 11 and the image decoding device 31 described above can be used for recording and reproduction of a moving image will be described with reference to FIG.

  FIG. 39A is a block diagram showing a configuration of a recording device PROD_C on which the image coding device 11 described above is mounted. As shown in (a) of FIG. 39, the recording device PROD_C obtains the encoded data obtained by encoding the moving image by the encoding unit PROD_C1, and the encoded data obtained by the encoding unit PROD_C1 to the recording medium PROD_M. And a writing unit PROD_C2 for writing. The image coding device 11 described above is used as the coding unit PROD_C1.

  The recording medium PROD_M may be (1) a type incorporated in the recording device PROD_C, such as a hard disk drive (HDD) or a solid state drive (SSD), or (2) an SD memory. It may be of a type connected to the recording device PROD_C, such as a card or a Universal Serial Bus (USB) flash memory, or (3) a DVD (Digital Versatile Disc) or a BD (Blu-ray Disc: Registration It may be loaded into a drive device (not shown) built in the recording device PROD_C, such as a trademark).

  In addition, the recording device PROD_C is a camera PROD_C3 for capturing a moving image as a supply source of the moving image input to the encoding unit PROD_C1, an input terminal PROD_C4 for inputting the moving image from the outside, and a reception for receiving the moving image The image processing unit PROD_C5 may further include an image processing unit PROD_C6 that generates or processes an image. Although (a) of FIG. 39 exemplifies a configuration in which the recording apparatus PROD_C includes all of these, a part may be omitted.

  Note that the receiving unit PROD_C5 may receive an uncoded moving image, and receives encoded data encoded by a transmission encoding scheme different from the recording encoding scheme. It may be In the latter case, it is preferable to interpose a transmission decoding unit (not shown) that decodes encoded data encoded by the transmission encoding scheme between the reception unit PROD_C5 and the encoding unit PROD_C1.

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

  (B) of FIG. 39 is a block diagram showing a configuration of a playback device PROD_D equipped with the image decoding device 31 described above. As shown in (b) of FIG. 39, the playback device PROD_D decodes the moving image by decoding the encoded data read by the reading unit PROD_D1 that reads the encoded data written to the recording medium PROD_M and the reading unit PROD_D1. And a decryption unit PROD_D2 to be obtained. The image decoding device 31 described above is used as the decoding unit PROD_D2.

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

  In addition, the playback device PROD_D is a display PROD_D3 that displays a moving image as a supply destination of the moving image output by the decoding unit PROD_D2, an output terminal PROD_D4 that outputs the moving image to the outside, and a transmission unit that transmits the moving image. It may further comprise PROD_D5. Although (b) of FIG. 39 exemplifies a configuration in which the playback device PROD_D includes all of these, a part may be omitted.

  The transmission unit PROD_D5 may transmit a non-encoded moving image, or transmit encoded data encoded by a transmission encoding method different from the recording encoding method. It may be In the latter case, an encoding unit (not shown) may be interposed between the decoding unit PROD_D2 and the transmission unit PROD_D5 for encoding moving pictures according to a transmission encoding scheme.

  As such a playback device PROD_D, for example, a DVD player, a BD player, an HDD player, etc. may be mentioned (in this case, the output terminal PROD_D4 to which a television receiver etc. is connected is the main supply destination of moving images) . In addition, television receivers (in this case, the display PROD_D3 is the main supply destination of moving images), digital signage (also referred to as an electronic signboard or electronic bulletin board, etc.), the display PROD_D3 or the transmission unit PROD_D5 is the main supply of moving images. First, desktop type PC (in this case, output terminal PROD_D4 or transmission unit PROD_D5 is the main supply destination of moving images), laptop type or tablet type PC (in this case, display PROD_D3 or transmission unit PROD_D5 is moving image) The main supply destination of the image), the smartphone (in this case, the display PROD_D3 or the transmission unit PROD_D5 is the main supply destination of the moving image), and the like are also examples of such a reproduction device PROD_D.

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

  In the latter case, each of the devices described above includes a CPU that executes instructions of a program that implements each function, a read only memory (ROM) that stores the program, a random access memory (RAM) that develops the program, the program, and various data. And a storage device (recording medium) such as a memory for storing the The object of the embodiment of the present invention is to record computer program readable program codes (execution format program, intermediate code program, source program) of control programs of the above-mentioned respective devices which are software for realizing the functions described above. The present invention can also be achieved by supplying a medium to each of the above-described devices, and a computer (or a CPU or an MPU) reading and executing a program code recorded on a 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, CDs (Compact Disc Read-Only Memory) / MO disks (Magneto-Optical disc). ) Disks including optical disks such as MD (Mini Disc) / DVD (Digital Versatile Disc) / CD-R (CD Recordable) / Blu-ray Disc (registered trademark), IC cards (including memory cards) Cards such as optical cards, mask ROMs / erasable programmable read-only memories (EPROMs) / electrically erasable and programmable read-only memories (EEPROMs) / semiconductor memories such as flash ROMs, or programmable logic devices (PLDs) And logic circuits such as FPGA (Field Programmable Gate Array) can be used.

  Further, each device may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. This communication network is not particularly limited as long as the program code can be transmitted. For example, the 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 network, mobile communication network, satellite communication network, etc. can be used. Also, the transmission medium that constitutes this communication network may be any medium that can transmit the program code, and is not limited to a specific configuration or type. For example, even if 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 rays such as IrDA (Infrared Data Association) or remote control , BlueTooth (registered trademark), IEEE 802.11 wireless, HDR (High Data Rate), NFC (Near Field Communication), DLNA (Digital Living Network Alliance (registered trademark), mobile phone network, satellite link, terrestrial digital broadcast network, etc. It can also be used wirelessly. The embodiment of the present invention may 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.

  Embodiments of the present invention are not limited to the above-described embodiments, and various modifications are possible 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.

(Cross-reference to related applications)
This application claims the benefit of priority to Japanese Patent Application filed on Sep. 27, 2016: Japanese Patent Application No. 2016-188791, the contents of which are incorporated by reference in their entirety. Is included in this book.

  An embodiment of the present invention is suitably applied to an image decoding apparatus that decodes encoded data obtained by encoding image data, and an image encoding apparatus that generates encoded data obtained by encoding image data. it can. Further, the present invention can be suitably applied to the data structure of encoded data generated by the image encoding device and referenced by the image decoding device.

11 image coding device 31 image decoding device 112 inter prediction parameter coding unit (predicted image generation device)
303 Inter prediction parameter decoding unit (predicted image generation device)
1122, 3032 AMVP prediction parameter deriving unit (affine motion vector deriving unit, affine motion vector deriving device)
30372 Affine prediction unit (Affine motion vector deriving unit, Affine motion vector deriving device)
309 Inter prediction image generation unit (prediction image generation unit)

Claims (17)

In an affine motion vector deriving device for deriving a motion vector of each of subblocks constituting a target PU,
The affine motion vector deriving device
The motion vector of each of the plurality of sub-blocks included in the target block is calculated with reference to the motion vector at the control point set in the reference block sharing the vertex with the target block,
According to at least one of the shape and the size of the target block, motion vectors of two control points are calculated to perform four parameter affine processing, or motion vectors of three control points are calculated and six parameter affine An affine motion vector deriving device characterized by switching whether to perform processing of In a predicted image generation device for generating a predicted image used for encoding or decoding of a moving image,
An affine motion vector deriving unit,
And a predicted image generation unit,
The affine motion vector deriving unit
The motion vector of each of the plurality of sub-blocks included in the target block is calculated with reference to the motion vector at the control point set in the reference block sharing the vertex with the target block,
According to at least one of the shape and the size of the target block, motion vectors of two control points are calculated to perform four parameter affine processing, or motion vectors of three control points are calculated and six parameter affine Switch the processing of the
The predicted image generation unit
A predicted image generation device characterized by generating a predicted image by referring to the motion vector of the control point. The affine motion vector deriving unit
The predicted image generation device according to claim 2, wherein the processing of six parameter affine is performed when the target block is a square, and the processing of four parameter affine is performed when the target block is not a square. The affine motion vector deriving unit
If the merge flag merge_flag indicates that the merge process is not to be performed, and the target block is not a square, a four-parameter affine process is performed;
When the merge flag merge_flag indicates that the merge process is not performed and the target block is a square, the PU affine mode flag pu_affine_mode_flag is decoded, and the PU affine mode flag pu_affine_mode_flag is a process of six parameter affine Is characterized in that processing of six parameters affine is performed, and when the PU affine mode flag pu_affine_mode_flag indicates that processing of four parameters affine is performed, processing of four parameters affine is performed. The predicted image generation device according to claim 2 or 3, wherein The affine motion vector deriving unit
The processing of six parameter affine is performed when the size of the target block is equal to or more than a predetermined threshold, and the processing of four parameter affine is performed when the size of the target block is not equal to or larger than the predetermined threshold. The prediction image generation device according to claim 1. The affine motion vector deriving unit
If the merge flag merge_flag indicates that merge processing is not to be performed, and the size of the target block is not equal to or larger than a predetermined threshold value, processing of four parameter affine is performed,
If the merge flag merge_flag indicates that merge processing is not performed and the size of the target block is equal to or larger than a predetermined threshold value, the PU affine mode flag pu_affine_mode_flag is decoded, and the PU affine mode flag pu_affine_mode_flag is 6-parameter affine processing is performed when processing of a 6-parameter affine is performed, and processing of 4-parameter affine processing is performed when the PU affine mode flag pu_affine_mode_flag indicates processing of a 4-parameter affine. The predicted image generation apparatus according to claim 5, wherein: The affine motion vector deriving unit
3. The predicted image generation device according to claim 2, wherein when the size of the target block is equal to or larger than a predetermined threshold and the target block is a square, processing of six parameters affine is performed. The affine motion vector deriving unit
If the merge flag merge_flag indicates that merge processing is not to be performed, and the size of the target block is not equal to or larger than a predetermined threshold, and the target block is not a square, four-parameter affine processing is performed. ,
(1) Merge flag merge_flag indicates that merge processing is not performed, and the size of the target block is equal to or larger than a predetermined threshold, or (2) merge flag merge_flag does not perform merge processing If the size of the target block is not equal to or greater than a predetermined threshold and the target block is a square, the PU affine mode flag pu_affine_mode_flag is decoded, and the PU affine mode flag pu_affine_mode_flag is 6 If the parameter affine processing is to be performed, the 6 parameter affine processing is performed. If the PU affine mode flag pu_affine_mode_flag indicates that the 4 parameter affine processing is to be performed, the 4 parameter affine processing is performed. The predicted image generation device according to claim 7, characterized in that: In a predicted image generation device for generating a predicted image used for encoding or decoding of a moving image,
An affine motion vector deriving unit,
And a predicted image generation unit,
The affine motion vector deriving unit
The motion vector of each of the plurality of sub-blocks included in the target block is calculated with reference to the motion vector at the control point set in the reference block sharing the vertex with the target block,
Depending on the shape and / or size of the reference block, motion vectors of two control points are calculated to perform 4-parameter affine processing, or motion vectors of three control points are calculated and 6-parameter affine. Switch the processing of the
The predicted image generation unit
A predicted image generation device characterized by generating a predicted image by referring to the motion vector of the control point. The affine motion vector deriving unit
10. The predicted image generation device according to claim 9, wherein processing of six parameter affines is performed when the reference block is a square, and processing of four parameter affine is performed when the reference block is not a square. The affine motion vector deriving unit
When the size of the reference block is equal to or greater than a predetermined threshold, six parameter affine processing is performed, and when the size of the target block is not equal to or larger than a predetermined threshold, four parameter affine processing is performed. The prediction image generation device according to claim 1. In a predicted image generation device for generating a predicted image used for encoding or decoding of a moving image,
An affine motion vector deriving unit,
And a predicted image generation unit,
The affine motion vector deriving unit
The motion vector of each of the plurality of sub-blocks included in the target block is calculated with reference to the motion vector at the control point set in the reference block sharing the vertex with the target block,
According to the shape of the target block or the shape of the reference block, the control points used for processing of the four parameter affine are changed;
The predicted image generation unit
A predicted image generation device characterized by generating a predicted image by referring to the motion vector of the control point. The affine motion vector deriving unit
When the target block is a square, a control point set in a reference block sharing each of two vertices on the diagonal of the target block is determined as the control point.
When the target block is not a square, a control point set in a reference block sharing each of two vertices sandwiching the long side of the target block is determined as the control point. The prediction image generation device according to claim 1. The affine motion vector deriving unit
If the reference block is a square, a control point set in a reference block sharing two diagonal vertices of the target block is determined as the control point.
The control point according to claim 12, wherein a control point set in a reference block sharing two vertices sandwiching a long side of the target block is determined as the control point when the reference block is not a square. Predictive image generation device. The affine motion vector deriving unit
If the shape of the reference block is a square, two vertices on the diagonal of the reference block are determined as the control points,
13. The predicted image generation device according to claim 12, wherein, when the reference block is not a square, two vertices sandwiching a long side of the reference block are determined as the control points. An apparatus for generating a predicted image according to any one of claims 2 to 15, comprising:
A moving picture decoding apparatus characterized by generating a decoded picture by adding or subtracting a residual signal to or from the predicted picture. An apparatus for generating a predicted image according to any one of claims 2 to 15, comprising:
A moving picture coding apparatus characterized in that a residual signal between the predicted picture and a picture to be coded is coded.

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