JP2019213018A - Image decoding apparatus and image encoding apparatus - Google Patents

Abstract

To prevent a memory band in an image decoding apparatus and an image encoding apparatus from being large.SOLUTION: An inter prediction image generation unit refers to motion information of a reference block that satisfies following conditions to generate a predicted image of a target block. The reference block is a block whose at least one of a vertical length (K) and a horizontal length (L) from a boundary of an encoding tree unit containing the target block out of blocks not adjacent to the target block is equal to or less than a predetermined value.SELECTED DRAWING: Figure 15

Description

  Embodiments described herein relate generally to an image decoding apparatus and an image encoding apparatus.

  In order to efficiently transmit or record a moving image, a moving image encoding device that generates encoded data by encoding the moving image, and a moving image that generates a decoded image by decoding the encoded data An image decoding device is used.

  Specific examples of the moving image encoding method include a method proposed in H.264 / AVC and HEVC (High-Efficiency Video Coding).

  In such a moving image coding system, an image (picture) constituting a moving image is a slice obtained by dividing the image, a coding tree unit (CTU: Coding Tree Unit) obtained by dividing the slice. ), A coding unit obtained by dividing the coding tree unit (sometimes referred to as a coding unit (CU)), and a prediction unit that is a block obtained by dividing the coding unit (PU) and a hierarchical structure composed of conversion units (TU), and encoded / decoded for each CU.

  In such a moving image coding method, a predicted image is usually generated based on a local decoded image obtained by encoding / decoding an input image, and the predicted image is generated from the input image (original image). A prediction residual obtained by subtraction (sometimes referred to as “difference image” or “residual image”) is encoded. Examples of the method for generating a predicted image include inter-screen prediction (inter prediction) and intra-screen prediction (intra prediction). Further, Non-Patent Document 1 can be cited as a technique for encoding and decoding moving images in recent years.

  For example, for inter prediction, a predicted image is generated by motion compensation between frames. In order to reduce the amount of code, information regarding motion compensation (motion compensation parameters) is often not directly encoded. For this reason, in inter prediction, motion compensation parameters are estimated based on the decoding situation around the prediction target block. As an example, in merge prediction, a list of motion compensation parameter candidates (merge candidates) is generated. Next, motion compensation of the prediction image of the prediction target block is performed using the merge candidate selected by the index from the list. The list of merge candidates includes spatial candidates derived based on motion information of a reference block that is a block different from the prediction target block. In the derivation of the spatial candidates, the reference block is not adjacent to the prediction target block to be decoded, but adjacent to the upper left block, the upper right adjacent block, the lower right adjacent block, and the prediction target block. It is selected from at least one of the blocks at the position.

  As a technique for deriving a motion vector on the decoder side, a block (subblock) adjacent to the prediction target block (subblock) is used as a template, and a motion vector of the prediction target block is derived using the motion vector of the adjacent block. Template matching is known.

"Algorithm Description of Joint Exploration Test Model 5", JVET-E1001, Joint Video Exploration Team (JVET) of ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11, 12-20 January 2017

  In merge prediction, a block belonging to a CTU different from the CTU to which the prediction target block belongs may become a reference block. The motion information of the block included in the CTU different from the CTU including the prediction target block is not stored in the internal memory of the image decoding apparatus and the image encoding apparatus. Therefore, external memory access is required to access the motion information. Therefore, the first problem that the memory band becomes large has occurred.

  In the conventional template matching, the motion vector of the CU decoded immediately before is used. For this reason, there has been a second problem that the predicted image generation process of the next CU cannot be started unless the decoding process in the CU processed immediately before is completed.

  An object of the present invention is to provide an image decoding device, an image encoding device, and a predicted image generation device that can solve at least one of the first and second problems.

  In order to solve the above-described problem, an image decoding device according to an aspect of the present invention is an image decoding device that decodes encoded data, and includes a prediction image generation unit that generates a prediction image of a target block. The image generation unit includes blocks that are not adjacent to the target block and have at least one of a vertical distance and a horizontal distance from a boundary of an encoding tree unit including the target block that is equal to or less than a predetermined value. A prediction image of the target block is generated with reference to the motion information.

  An image decoding apparatus according to an aspect of the present invention is an image decoding apparatus that decodes encoded data, and includes a motion information deriving unit that derives motion information of a target block and the target block with reference to the motion information. The motion information deriving unit generates a motion image of the target block by performing template matching with reference to a decoded template region set in accordance with the target block. The information is derived, and the motion information deriving unit does not set the pixel included in the block processed immediately before the target block in the template region.

  An image decoding apparatus according to an aspect of the present invention is an image decoding apparatus that decodes encoded data, and includes a motion information deriving unit that derives motion information of a target block and the target block with reference to the motion information. The motion information deriving unit generates a motion image of the target block by performing template matching with reference to a decoded template region set in accordance with the target block. Information is derived, and an index is allocated to the target block, and the motion information deriving unit sets the template area according to the index allocated to the target block.

  An image decoding apparatus according to an aspect of the present invention is an image decoding apparatus that decodes encoded data, and includes a motion information deriving unit that derives motion information of a target block and the target block with reference to the motion information. The motion information deriving unit generates a motion image of the target block by performing template matching with reference to a decoded template region set in accordance with the target block. The information is derived, and the motion information deriving unit sets only the pixels located above the target block as candidates for the template region.

  An image decoding apparatus according to an aspect of the present invention is an image decoding apparatus that decodes encoded data, and includes a motion information deriving unit that derives motion information of a target block and the target block with reference to the motion information. The motion information deriving unit generates a motion image of the target block by performing template matching with reference to a decoded template region set in accordance with the target block. The information is derived, and the motion information deriving unit sets the template region according to how the target block is a divided block.

An image decoding apparatus according to an aspect of the present invention is an image decoding apparatus that decodes encoded data, and includes a motion information deriving unit that derives motion information of a target block and the target block with reference to the motion information. A predicted image generation unit that generates a predicted image of the motion information, the motion information derivation unit,
Processing for deriving motion information of the target block by performing template matching with reference to the decoded template region set according to the target block, and going back from the downstream side in the raster scan order to the upstream side in the raster scan order The target block is set according to the scan order including at least part of the order.

  An image decoding apparatus according to an aspect of the present invention is an image decoding apparatus that decodes encoded data, a motion information deriving unit that derives motion information of a target block, and the target by referring to the motion information. A prediction image generation unit that generates a prediction image of the block; and a scan order setting unit that sets a scan order of the block in the prediction image generation unit, wherein the motion information deriving unit is set according to the target block By performing template matching with reference to the decoded template region, the motion information of the target block is derived, and the scan order setting unit refers to the flag included in the encoded data, and the prediction image generation unit Sets the scan order of blocks at.

  In order to solve the above-described problem, an image encoding device according to an aspect of the present invention is an image encoding device that encodes a residual between a predicted image and an encoding target image, and the prediction image of the target block is A prediction image generation unit for generating, wherein the prediction image generation unit includes at least a vertical distance and a horizontal distance from a boundary of a coding tree unit including the target block among blocks not adjacent to the target block. A prediction image of the target block is generated with reference to the motion information of a block that is less than or equal to a predetermined value.

  An image encoding device according to an aspect of the present invention is an image encoding device that encodes a residual between a predicted image and an encoding target image, and a motion information deriving unit that derives motion information of the target block. And a predicted image generating unit that generates a predicted image of the target block with reference to the motion information, and the motion information deriving unit referred to the encoded template region set according to the target block By performing template matching, the motion information of the target block is derived, and the motion information deriving unit does not set the pixel included in the block processed immediately before the target block in the template region.

  An image encoding device according to an aspect of the present invention is an image encoding device that encodes a residual between a predicted image and an encoding target image, and a motion information deriving unit that derives motion information of the target block. And a predicted image generating unit that generates a predicted image of the target block with reference to the motion information, and the motion information deriving unit referred to the encoded template region set according to the target block By performing template matching, the motion information of the target block is derived, an index is allocated to the target block, and the motion information deriving unit is configured according to the index allocated to the target block, Set the template area.

  An image encoding device according to an aspect of the present invention is an image encoding device that encodes a residual between a predicted image and an encoding target image, and a motion information deriving unit that derives motion information of the target block. And a predicted image generating unit that generates a predicted image of the target block with reference to the motion information, and the motion information deriving unit referred to the encoded template region set according to the target block By performing template matching, the motion information of the target block is derived, and the motion information deriving unit sets only pixels located above the target block as candidates for the template.

  An image encoding device according to an aspect of the present invention is an image encoding device that encodes a residual between a predicted image and an encoding target image, and a motion information deriving unit that derives motion information of the target block. And a predicted image generation unit that generates a predicted image of the target block with reference to the motion information, and the motion information deriving unit refers to a template that refers to a decoded template region set according to the target block By performing matching, the motion information of the target block is derived, and the motion information deriving unit changes the region set in the template according to how the target block is a divided block. To do.

  An image encoding device according to an aspect of the present invention is an image encoding device that encodes a residual between a predicted image and an encoding target image, and a motion information deriving unit that derives motion information of the target block. And a predicted image generating unit that generates a predicted image of the target block with reference to the motion information, and the motion information deriving unit refers to a template matching that refers to a decoded template region set according to the target block As a result, the motion information of the target block is derived, and the target block is set according to the scan order including at least a part of the processing order going back from the downstream side in the raster scan order to the upstream side in the raster scan order.

  An image encoding device according to an aspect of the present invention is an image encoding device that encodes a residual between a predicted image and an encoding target image, and a motion information deriving unit that derives motion information of the target block. A prediction image generation unit that generates a prediction image of the target block with reference to the motion information, and a scan order setting unit that sets a scan order of the blocks in the prediction image generation unit, and the motion information deriving unit Derives the motion information of the target block by performing template matching with reference to the encoded template region set according to the target block, and the scan order setting unit converts the encoded data into the encoded data. A flag indicating the scan order of blocks in the predicted image generation unit is included.

  According to the above configuration, at least one of the first and second problems can be solved.

It is a figure which shows the hierarchical structure of the data of the encoding stream which concerns on this embodiment. It is a figure which shows the pattern of PU division | segmentation mode. (A) to (h) show the partition shapes when the PU partitioning modes are 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 the 1st embodiment. It is the schematic which shows the structure of the image decoding apparatus which concerns on this 1st Embodiment. It is the schematic which shows the structure of the inter estimated image generation part of the image coding apparatus which concerns on the 1st embodiment. It is the schematic which shows the structure of the merge prediction parameter derivation | leading-out part which concerns on the 1st embodiment. It is the schematic which shows the structure of the merge candidate derivation | leading-out part which concerns on the 1st embodiment. It is the schematic which shows the structure of the AMVP prediction parameter derivation | leading-out part which concerns on the 1st embodiment. It is the schematic which shows the structure of the inter prediction parameter encoding part of the image coding apparatus which concerns on the 1st embodiment. It is the schematic which shows the structure of the inter estimated image generation part which concerns on the 1st embodiment. It is the schematic which shows the structure of the inter prediction parameter decoding part which concerns on the 1st embodiment. (A) is a figure for demonstrating bilateral matching (Bilateral matching). (B) is a figure for demonstrating template matching (Template matching). It is a schematic diagram which shows an example of the determination of the availability determination part which concerns on the modification of this 1st Embodiment. It is a schematic diagram which shows another example of the determination of the availability determination part which concerns on the modification of this 1st Embodiment. It is a schematic diagram which shows another example of the determination of the availability determination part which concerns on the modification of the 1st embodiment. (A) to (f) is a diagram showing division of coding nodes in the image decoding apparatus according to the second embodiment. It is a figure which shows the branch type signaling performed by the image decoding apparatus according to the second embodiment. It is a block diagram which shows the structure of the image decoding apparatus which concerns on the 2nd embodiment. It is a flowchart explaining the decoding process which concerns on the 2nd embodiment. It is a flowchart which shows the outline | summary of an example of the flow of the BT / TT information decoding process which concerns on the 2nd embodiment. It is a figure which shows an example of the syntax regarding the QT information decoding process which concerns on the 2nd embodiment. It is a figure which shows an example of the syntax regarding the QT information decoding process which concerns on the 2nd embodiment. It is a figure which shows an example of the syntax regarding the BT / TT information decoding process which concerns on the 2nd embodiment. It is a figure which shows an example of the syntax regarding the TT information decoding process which concerns on the 2nd embodiment. It is a figure which shows an example of the syntax regarding the BT information decoding process which concerns on the 2nd embodiment. (A) to (c) is a diagram illustrating an example of a template region set by the matching motion deriving unit according to the second embodiment. (A) to (d) is a diagram showing an example of a template region set by the matching motion deriving unit according to the second embodiment. (A) to (c) is a diagram illustrating an example of a template region set by the matching motion deriving unit according to the second embodiment. (A) to (d) is a diagram showing another example of the template region set by the matching motion deriving unit according to the second embodiment. (A) And (b) is a figure which shows another example of the template area | region which the matching motion derivation part concerning this 2nd embodiment sets up. (A) to (c) is a diagram showing another example of the template region set by the matching motion deriving unit according to the second embodiment. (A) And (b) is a figure which shows another example of the template area | region which the matching motion derivation | leading-out part which concerns on the 2nd embodiment sets. (A) to (c) is a diagram showing still another example of the template region set by the matching motion deriving unit according to the second embodiment. (A) to (d) is a diagram showing still another example of the template region set by the matching motion deriving unit according to the second embodiment. (A) to (c) is a diagram showing still another example of the template region set by the matching motion deriving unit according to the second embodiment. (A) to (c) is a diagram showing still another example of the template region set by the matching motion deriving unit according to the second embodiment. (A) to (d) is a diagram showing still another example of the template region set by the matching motion deriving unit according to the second embodiment. (A) to (c) is a diagram showing still another example of the template region set by the matching motion deriving unit according to the second embodiment. (A) to (d) is a diagram showing a modification of the template region set by the matching motion deriving unit according to the second embodiment. (A) to (c) is a diagram showing an example of a scan order of divided blocks according to the second embodiment. (D) to (f) are other examples of the scan order of the divided blocks according to the second embodiment. (A) to (c) is a diagram showing still another example of the template region set by the matching motion deriving unit according to the second embodiment. (A) to (d) is a diagram showing still another example of the template region set by the matching motion deriving unit according to the second embodiment. (A) to (c) is a diagram showing still another example of the template region set by the matching motion deriving unit according to the second embodiment. It is a figure which shows an example of the syntax which changes a scan order according to alt_cu_scan_flag with respect to the block by which QT division | segmentation which concerns on the 2nd embodiment was carried out. It is a figure which shows an example of the syntax which changes a scanning order according to alt_cu_scan_flag with respect to the block by which TT division | segmentation which concerns on this 2nd Embodiment. It is a figure which shows an example of the syntax which changes a scanning order according to alt_cu_scan_flag with respect to the block by which BT division which concerns on the 2nd embodiment was carried out. It is the figure shown about the structure of the transmitter which mounts the image coding apparatus which concerns on this embodiment, and the receiver which mounts an image decoding apparatus. (A) shows a transmission device equipped with an image encoding device, and (b) shows a reception device equipped with an image decoding device. It is the figure shown about the structure of the recording device carrying the image coding apparatus which concerns on this embodiment, and the reproducing | regenerating apparatus carrying an image decoding apparatus. (A) shows a recording device equipped with an image encoding device, and (b) shows a playback device equipped with an image decoding device. It is the schematic which shows the structure of the image transmission system which concerns on this embodiment.

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

  FIG. 48 is a schematic diagram illustrating a 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 encoding an image to be encoded, decodes the transmitted code, and displays an image. The image transmission system 1 includes 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 indicating a single layer image or a plurality of layers of images is input to the image encoding device 11. A layer is a concept used to distinguish a plurality of pictures when there are one or more pictures constituting a certain time. For example, when the same picture is encoded with a plurality of layers having different image quality and resolution, scalable encoding is performed, and when a picture of a different viewpoint is encoded with a plurality of layers, view scalable encoding is performed. When prediction is performed between pictures of a plurality of layers (inter-layer prediction, inter-view prediction), encoding efficiency is greatly improved. Further, even when prediction is not performed (simultaneous casting), encoded data can be collected.

  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 network (LAN), or a combination thereof. The network 21 is not necessarily limited to a bidirectional communication network, and may be a unidirectional communication network that transmits broadcast waves such as terrestrial digital broadcasting and satellite broadcasting. The network 21 may be replaced with a storage medium that records an encoded stream Te such as a DVD (Digital Versatile Disc) or a BD (Blue-ray Disc).

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

  The image display device 41 displays all or part of one or a plurality of 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 addition, in the spatial scalable coding and SNR scalable coding, when the image decoding device 31 and the image display device 41 have a high processing capability, a high-quality enhancement layer image is displayed and only a lower processing capability is provided. Displays a base layer image that does not require higher processing capability and display capability as an extension layer.

<Operator>
The operators used in this specification are described below.

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

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

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

<Structure of encoded stream Te>
Prior to detailed description of the image encoding device 11 and the image decoding device 31 according to the present embodiment, a data structure of an 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 illustrating a hierarchical structure of data in the encoded stream Te. The encoded stream Te illustratively includes a sequence and a plurality of pictures constituting the sequence. (A) to (f) of FIG. 1 respectively show an encoded video sequence defining a sequence SEQ, an encoded picture defining a picture PICT, an encoded slice defining a slice S, and an encoded slice defining a slice data It is a figure which shows the coding unit (Coding Unit; CU) contained in the coding tree unit contained in data and coding slice data, and a coding tree unit.

(Encoded video sequence)
In the encoded video sequence, a set of data referred to by the image decoding device 31 for decoding 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. Includes SEI (Supplemental Enhancement Information). Here, the value indicated after # indicates the layer ID. Although FIG. 1 shows an example in which encoded data of # 0 and # 1, that is, layer 0 and layer 1, exists, the type of layer and the number of layers are not dependent on this.

  The video parameter set VPS is a set of encoding parameters common to a plurality of moving images, a plurality of layers included in the moving image, and encoding parameters related to individual layers in a moving image composed of a plurality of layers. A set is defined.

  In the sequence parameter set SPS, a set of encoding parameters referred to by the image decoding device 31 in order to decode the target sequence is defined. For example, the width and height of the picture are defined. A plurality of SPSs may exist. In that case, one of a plurality of SPSs is selected from the PPS.

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

(Encoded picture)
In the coded picture, a set of data referred to by the image decoding device 31 in order to decode the picture PICT to be processed is defined. As shown in FIG. 1B, the picture PICT includes slices S0 to S _NS-1 (NS is the total number of slices included in the picture PICT).

Hereinafter, when it is not necessary to distinguish each of the slices S0 to SNS _-1 , the subscripts may be omitted. The same applies to data included in an encoded stream Te described below and to which other subscripts are attached.

(Encoded slice)
In the coded slice, a set of data referred to by the image decoding device 31 for decoding the slice S to be processed is defined. As shown in FIG. 1C, the slice S includes a slice header SH and slice data SDATA.

  The slice header SH includes an encoding parameter group that is referred to by the image decoding device 31 in order to determine a decoding method of the target slice. Slice type designation information (slice_type) for designating a slice type is an example of an encoding parameter included in the slice header SH.

  As slice types that can be specified by the slice type specification information, (1) I slice using only intra prediction at the time of encoding, (2) P slice using unidirectional prediction or intra prediction at the time of encoding, (3) B-slice using unidirectional prediction, bidirectional prediction, or intra prediction at the time of encoding may be used.

  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.

(Encoded slice data)
In the encoded slice data, a set of data referred to by the image decoding device 31 for decoding the slice data SDATA to be processed is defined. The slice data SDATA includes a coding tree unit (CTU) as shown in FIG. A CTU is a block of a fixed size (for example, 64x64) that constitutes a slice, and is sometimes called a maximum coding unit (LCU: Large Coding Unit).

(Encoding tree unit)
As shown in (e) of FIG. 1, a set of data referred to by the image decoding device 31 in order to decode the encoding 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 partitioning is referred to as a coding node (CN). An intermediate node of the quadtree is an encoding node, and the encoding tree unit itself is defined as the highest encoding node. The CTU includes a split flag (cu_split_flag), and when cu_split_flag is 1, it is split into four coding nodes CN. When cu_split_flag is 0, the coding node CN is not divided and has one coding unit (CU: Coding Unit) as a node. The encoding unit CU is a terminal node of the encoding node and is not further divided. The encoding unit CU is a basic unit of the encoding process.

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

(Encoding unit)
As shown in (f) of FIG. 1, a set of data referred to by the image decoding device 31 in order to decode an encoding unit to be processed is defined. Specifically, the encoding unit includes a prediction tree, a conversion 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 (a reference picture index, a motion vector, etc.) of each prediction unit (PU) obtained by dividing the coding unit into one or a plurality of parts is defined. In other words, the prediction unit is one or a plurality of non-overlapping areas constituting the encoding unit. The prediction tree includes one or a plurality of prediction units obtained by the above-described division. Hereinafter, a prediction unit obtained by further dividing the prediction unit is referred to as a “sub-block”. The sub block is composed of a plurality of pixels. When the sizes of the prediction unit and the sub-block are equal, the number of sub-blocks in the prediction unit is one. If the prediction unit is larger than the size of the sub-block, the prediction unit is divided into sub-blocks. For example, when the prediction unit is 8 × 8 and the sub-block is 4 × 4, the prediction unit is divided into four sub-blocks that are divided into two horizontally and two vertically.

  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 within the same picture, and inter prediction refers to prediction processing performed between different pictures (for example, between display times and between layer images).

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

  Also, in the case of inter prediction, the division method is encoded by the PU division mode (part_mode) of encoded data, 2Nx2N (same size as the encoding unit), 2NxN, 2NxnU, 2NxnD, Nx2N, nLx2N, nRx2N, and NxN etc. 2NxN and Nx2N indicate 1: 1 symmetrical 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, and PU3 in this order.

  2A to 2H specifically illustrate the shape of the partition (the position of the boundary of the PU partition) in each PU partition mode.

  In the transform tree, the encoding unit is divided into one or a plurality of 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 areas that make up a coding unit. The conversion tree includes one or a plurality of conversion units obtained by the above division.

  There are two types of division in the conversion tree: one in which an area having the same size as that of the encoding unit is allocated as a conversion unit, and the other in division by recursive quadtree division as in the above-described CU division.

  The conversion process is performed for each conversion unit.

(Prediction parameter)
A prediction image of a prediction unit (PU: Prediction Unit) is derived from a prediction parameter associated with the PU. The prediction parameters include a prediction parameter for intra prediction or a prediction parameter for inter prediction. 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 or not reference picture lists called L0 list and L1 list are used, respectively, and a reference picture list corresponding to a value of 1 is used. In this specification, when “flag indicating whether or not it is XX” is described, when the flag is not 0 (for example, 1) is XX, 0 is not XX, and logical negation, logical product, etc. 1 is treated as true and 0 is treated as false (the same applies hereinafter). However, other values can be used as true values and false values in an actual apparatus or method.

  Syntax elements for deriving inter prediction parameters included in the encoded data include, for example, PU partition mode part_mode, flag merge_flag, merge index merge_idx, inter prediction identifier inter_pred_id merge c, reference picture index refIdxLX, prediction vector index mvp_LX_idx There is a difference vector mvdLX.

(Reference picture list)
The reference picture list is a list including reference pictures stored in the reference picture memory 306. FIG. 3 is a conceptual diagram illustrating an example of a reference picture and a reference picture list. In FIG. 3A, a rectangle is a picture, an arrow is a picture reference relationship, a horizontal axis is time, I, P, and B in the rectangle are intra pictures, uni-predictive pictures, bi-predictive pictures, and numbers in the rectangles are decoded. Show the order. As shown in the figure, the decoding order of pictures is I0, P1, B2, B3, and B4, and the display order is I0, B3, B2, B4, and P1. FIG. 3B shows an example of the reference picture list. The reference picture list is a list representing candidate reference pictures, and one picture (slice) may have one or more reference picture lists. In the illustrated example, the target picture B3 has two reference picture lists, an L0 list RefPicList0 and an L1 list RefPicList1. When the target picture is B3, the reference pictures are I0, P1, and B2, and the reference picture has these pictures as elements. In each prediction unit, which picture in the reference picture list RefPicListX is actually referred to is specified 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 prediction and AMVP prediction)
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 in which the prediction list use flag predFlagLX (or inter prediction identifier inter_pred_idc), the reference picture index refIdxLX, and the motion vector mvLX are not included in the encoded data and are derived from the prediction parameters of already processed neighboring PUs, 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 for identifying the prediction vector mvpLX and a difference vector mvdLX.

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

  The merge index merge_idx is an index indicating whether any prediction parameter is used as a prediction parameter of a decoding target PU among prediction parameter candidates (merge candidates) derived from a PU for which processing has been completed.

(Motion vector)
The motion vector mvLX indicates a shift amount between blocks on two different pictures. A prediction vector and a difference vector related 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 use flag predFlagLX)
The relationship between the inter prediction identifier inter_pred_idc and the prediction list use flags predFlagL0 and predFlagL1 is as follows and can be converted into each other.

inter_pred_idc = (predFlagL1 << 1) + predFlagL0
predFlagL0 = inter_pred_idc & 1
predFlagL1 = inter_pred_idc >> 1
Note that a prediction list use flag or an inter prediction identifier may be used as the inter prediction parameter. 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 use flag.

(Configuration of image decoding device)
Next, the configuration of the image decoding device 31 according to the present embodiment will be described. FIG. 5 is a schematic diagram illustrating a 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 inversely. A quantization / inverse transform unit 311 and an adder 312 are included.

  The prediction parameter decoding unit 302 includes an inter prediction parameter decoding unit 303 and an intra prediction parameter decoding unit 304. The predicted image generation unit 308 includes an inter predicted image generation unit 309 and an intra predicted image generation unit 310.

  The entropy decoding unit 301 performs entropy decoding on an encoded stream Te input from the outside, and separates and decodes 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. Some of the separated codes are, for example, a prediction mode predMode, a PU partition mode part_mode, a merge flag merge_flag, a merge index merge_idx, an inter prediction identifier inter_pred_idc, a reference picture index refIdxLX, a prediction vector index mvp_LX_idx, and a difference vector mvdLX. Control of which code is decoded is performed based on an instruction from the prediction parameter decoding unit 302. The entropy decoding unit 301 outputs the quantized coefficient to the inverse quantization / inverse transform unit 311. In the coding process, this quantization coefficient is applied to the residual signal by DCT (Discrete Cosine Transform), DST (Discrete Sine Transform), KLT (Karyhnen Loeve Transform) It is a coefficient obtained by performing frequency conversion such as

  Based on the code input from the entropy decoding unit 301, the inter prediction parameter decoding unit 303 refers to the prediction parameter stored in the prediction parameter memory 307 and decodes the inter prediction parameter.

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

  Based on the code input from the entropy decoding unit 301, the intra prediction parameter decoding unit 304 refers to the prediction parameter stored in the prediction parameter memory 307 and decodes the intra prediction parameter. The intra prediction parameter is a parameter used in a process of predicting a CU within 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 depending on the luminance and color difference. In this case, the intra prediction parameter decoding unit 304 decodes the luminance prediction mode IntraPredModeY as the luminance prediction parameter and the color difference prediction mode IntraPredModeC as the color difference prediction parameter. The luminance prediction mode IntraPredModeY is a 35 mode, and corresponds to planar prediction (0), DC prediction (1), and direction prediction (2 to 34). The color difference prediction mode IntraPredModeC uses any one of the planar prediction (0), the DC prediction (1), the direction prediction (2 to 34), and the LM mode (35). The intra prediction parameter decoding unit 304 decodes a flag indicating whether IntraPredModeC is the same mode as the luminance mode. If the flag indicates that the mode is the same as the luminance mode, IntraPredModeC is assigned to IntraPredModeC, and the flag indicates luminance. If 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 filters such as a deblocking filter, a sample adaptive offset (SAO), and an adaptive loop filter (ALF) to the decoded image of the CU generated by the adding unit 312.

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

  The prediction parameter memory 307 stores the prediction parameter at a predetermined position for each decoding target picture and 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 stored inter prediction parameters include, for example, a prediction list utilization 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 prediction parameters from the prediction parameter decoding unit 302. Further, the predicted image generation unit 308 reads a reference picture from the reference picture memory 306. The prediction image generation unit 308 generates a prediction image of a PU or sub-block using the input prediction parameter and the read reference picture (reference picture block) 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 (reference picture block). To generate a prediction image of a PU or sub-block.

  The inter prediction image generation unit 309 performs a motion vector on the basis of the decoding target PU from the reference picture indicated by the reference picture index refIdxLX for a reference picture list (L0 list or L1 list) having a prediction list use flag predFlagLX of 1. The reference picture block at the position indicated by mvLX is read 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 prediction image of the PU. The inter prediction image generation unit 309 outputs the generated prediction image of the PU to the addition unit 312. Here, a reference picture block is a set of pixels on a reference picture (usually called a block because it is a rectangle), and is an area that is referred to in order to generate a predicted image of a PU or sub-block.

  When the prediction mode predMode indicates the intra prediction mode, the intra predicted 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 that are pictures to be decoded and are in a predetermined range from the decoding target PUs among the 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 decoding target PU sequentially moves in the so-called raster scan order, and differs depending on the intra prediction mode. The raster scan order is an order in which each row is sequentially moved from the left end to the right end in each picture from the upper end to the lower end.

  The intra predicted image generation unit 310 performs prediction in the prediction mode indicated by the intra prediction mode IntraPredMode based on the read adjacent PU, and generates a predicted image of the PU. The intra predicted image generation unit 310 outputs the generated predicted image of the PU to the adding unit 312.

  The inverse quantization / inverse transform unit 311 performs inverse quantization on the quantization coefficient input from the entropy decoding unit 301 to obtain a transform coefficient. The inverse quantization / inverse transform unit 311 performs inverse frequency transform such as inverse DCT, inverse DST, and inverse KLT on the obtained transform coefficient, and calculates a residual signal. The inverse quantization / inverse transform unit 311 outputs the calculated residual signal to the adder 312.

  The addition unit 312 adds the prediction image of the PU input from the inter prediction image generation unit 309 or the intra prediction image generation unit 310 and the residual signal input from the inverse quantization / inverse conversion unit 311 for each pixel, Generate a decoded PU image. The adding unit 312 stores the generated decoded image of the PU in the reference picture memory 306, and outputs a decoded image Td obtained by integrating the generated decoded image of the PU for each picture to the outside.

(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 illustrating 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, an addition unit 3038, a merge prediction parameter derivation unit 3036, and a sub-block prediction 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 partition 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, and difference vector mvdLX are extracted.

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

  When the merge flag merge_flag is 0, that is, indicates the AMVP prediction mode, the inter prediction parameter decoding control unit 3031 uses the entropy decoding unit 301 to extract AMVP prediction parameters from the encoded data. Examples of AMVP prediction parameters include an inter prediction identifier inter_pred_idc, a reference picture index refIdxLX, a prediction vector index mvp_LX_idx, and a 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 3038. The adding unit 3038 adds the prediction vector mvpLX and the difference vector mvdLX to derive a motion vector.

  When the merge flag merge_flag is 1, that is, indicates the merge prediction mode, the inter prediction parameter decoding control unit 3031 extracts the 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 subblock prediction parameter deriving unit 3037 divides the PU into a plurality of subblocks according to the value of the subblock prediction mode flag subPbMotionFlag, and derives a motion vector in units of subblocks. That is, in the sub-block prediction mode, the prediction block is predicted in units of blocks as small as 4x4 or 8x8. In the image encoding device 11 to be described later, a sub-block prediction mode is used for a method in which a CU is divided into a plurality of partitions (PUs such as 2NxN, Nx2N, and NxN) and the syntax of prediction parameters is encoded in units of partitions. Since a plurality of sub-blocks are grouped into a set and the syntax of the prediction parameter is encoded for each set, motion information of a large number of sub-blocks can be encoded with a small amount of code.

  More specifically, the sub-block prediction parameter derivation unit 3037 includes at least one of a spatio-temporal sub-block prediction unit 30371 and a matching motion derivation unit 30373 that perform sub-block prediction in the sub-block prediction mode.

(Subblock prediction mode flag)
Here, a method for deriving a sub-block prediction mode flag subPbMotionFlag indicating whether a prediction mode of a certain PU is a 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 a sub-block prediction mode flag subPbMotionFlag based on which of later-described spatial sub-block prediction SSUB, temporal sub-block prediction TSUB, and matching motion derivation MAT is used. For example, when the prediction mode selected by a certain PU is N (for example, N is a label indicating the selected merge candidate), the sub-block prediction mode flag subPbMotionFlag may be derived by the following equation.

subPbMotionFlag = (N == TSUB) || (N == SSUB) || (N == MAT)
Here, || represents a logical sum (the same applies hereinafter).

  The image decoding device 31 and the image encoding device 11 may be configured to perform some predictions among the spatial sub-block prediction SSUB, the temporal sub-block prediction TSUB, and the matching motion derivation MAT. . That is, when the image decoding device 31 and the image encoding device 11 are configured to perform spatial subblock prediction SSUB, the subblock prediction mode flag subPbMotionFlag may be derived as follows.

subPbMotionFlag = (N == SSUB))
(Sub-block prediction unit)
Next, the sub-block prediction unit will be described.

(Spatio-temporal sub-block prediction unit 30371)
The spatio-temporal sub-block prediction unit 30371 calculates the target PU from the motion vector of the PU on the reference image temporally adjacent to the target PU (for example, the immediately preceding picture) or the motion vector of the PU spatially adjacent to the target PU. The motion vector of the sub-block obtained by dividing is derived. Specifically, the motion vector spMvLX [xi] [yi] (xi = xPb) of each sub-block in the target PU is scaled by matching the motion vector of the PU on the reference image with the reference picture referenced by the target PU. + nSbW * i, yj = yPb + nSbH * j, i = 0, 1, 2, ..., nPbW / nSbW-1, j = 0, 1, 2, ..., nPbH / nSbH-1) Derived (temporal sub-block prediction). Here, (xPb, yPb) is the upper left coordinate of the target PU, nPbW, nPbH are the size of the target PU, and nSbW, nSbH are the sizes of the sub-blocks.

  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 [ xi] [yi] (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 (spatial sub-block prediction).

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

(Matching motion deriving unit 30373)
The matching motion deriving unit 30373 derives a motion vector spMvLX of a block or sub-block constituting the PU by performing a matching process of either bilateral matching or template matching. FIG. 13 is a diagram for explaining (a) bilateral matching and (b) template matching. The matching motion derivation mode is selected as one merge candidate (matching candidate) in the merge mode.

  The matching motion deriving unit 30373 derives a motion vector by matching regions in a plurality of reference images, assuming that the object moves at a constant velocity. In bilateral matching, it is assumed that a certain object passes through a certain region of the reference image A, a target PU of the target picture Cur_Pic, and a certain region of the reference image B with constant velocity motion, and matching between the reference images A and B To derive the motion vector of the target PU. In template matching, it is assumed that the motion vector of the target PU adjacent region and the target PU are equal, and motion is performed by matching motion compensated images between the target PU adjacent region Temp_Cur (template) and the reference block adjacent region Temp_L0 on the reference picture. Derive a vector. The matching motion derivation unit divides the target PU into a plurality of sub-blocks, and performs bilateral matching or template matching (to be described later) in units of the divided sub-blocks, thereby sub-block motion vectors spMvLX [xi] [yi] (xi = xPb + nSbW * i, yj = yPb + nSbH * j, i = 0, 1, 2, ..., nPbW / nSbW-1, j = 0, 1, 2, ..., nPbH / nSbH-1 ) Is derived.

  FIG. 13B is a diagram for explaining template matching among the above matching processes.

  As shown in FIG. 13B, in template matching, one reference picture is referred to at a time in order to derive a motion vector of the sub-block Cur_block in the current picture Cur_Pic.

More specifically, first, for example, an area in a reference image Ref0 (referred to as reference picture A) designated by a reference picture index refIdxL0,
(XPos, yPos) = (xCur + MV0_x, yCur + MV0_y)
The reference block Block_A having the upper left coordinates (xPos, yPos) specified by is specified. Here, (xCur, yCur) is the upper left coordinate of the sub-block Cur_block.

  Next, template region Temp_Cur adjacent to sub-block Cur_block in target picture Cur_Pic and template region Temp_L0 adjacent to Block_A in reference picture A are set. In the example illustrated in FIG. 13B, the template region Temp_Cur is configured by 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 area Temp_L0 is composed of an area adjacent to the upper side of Block_A and an area adjacent to the left side of Block_A.

  Next, it is determined (MV0_x, MV0_y) that minimizes the matching cost between Temp_Cur and TempL0, and becomes the motion vector spMvL0 assigned to the sub-block.

In the template matching, the same processing may be performed on the reference image Ref1 different from the reference image Ref0. In this case, an area in the reference image Ref1 (referred to as reference picture A) designated by the reference picture index refIdxL1,
(XPos, yPos) = (xCur + MV1_x, yCur + MV1_y)
The reference block Block_A having the upper left coordinates (xPos, yPos) specified by is specified, and the template area Temp_L1 adjacent to Block_A in the reference picture A is set.
Finally, it is determined (MV1_x, MV1_y) that minimizes the matching cost between Temp_Cur and TempL1, and becomes the motion vector spMvL1 assigned to the sub-block.

  Also, template matching may be performed on two reference images Ref0 and Ref1. In this case, the matching of one reference image Ref0 and the matching of one reference image Ref1 described above are sequentially performed.

  FIG. 7 is a schematic diagram illustrating a configuration of the merge prediction parameter deriving 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 candidates input from the merge candidate derivation unit 30361. The merge candidate includes 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 a merge candidate using the motion vector of the adjacent PU that has already been decoded and the reference picture index refIdxLX as they are.

(Spatial merge candidate derivation process)
As the spatial merge candidate derivation process, the merge candidate derivation unit 30361 reads 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 predicted parameters are derived as merge candidates. The prediction parameter to be read is a prediction parameter related to each of the PUs within a predetermined range from the decoding target PU (for example, all or part of the PUs in contact with the lower left end, the upper left end, and the upper right end of the decoding target PU, respectively). is there.

(Time merge candidate derivation process)
As the temporal merge derivation process, the merge candidate derivation unit 30361 reads the prediction parameter of the PU in the reference image including the lower right coordinate of the decoding target PU from the prediction parameter memory 307 and sets it as a merge candidate. The reference picture designation method may be, for example, the reference picture index refIdxLX designated in the slice header, or may be designated using the smallest reference picture index refIdxLX of the PU adjacent to the decoding target PU.

  The merge candidate selection unit 30362 selects, from the merge candidates stored in the merge candidate storage unit 30363, a merge candidate to which an index corresponding to the merge index merge_idx input from the inter prediction parameter decoding control unit 3031 is assigned. As an inter prediction parameter. The merge candidate selection unit 30362 stores the selected merge candidate in the prediction parameter memory 307 and outputs it to the prediction image generation unit 308.

  FIG. 9 is a schematic diagram illustrating a 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 mvLX stored in the prediction parameter memory 307 based on the reference picture index refIdx, and the vector candidate storage unit 3035 prediction vector candidate list mvpListLX [] To store.

  The vector candidate selection unit 3034 selects the motion vector mvpListLX [mvp_LX_idx] indicated by the prediction vector index mvp_LX_idx from the prediction vector candidates in the prediction vector candidate list mvpListLX [] as the prediction vector mvpLX. The vector candidate selection unit 3034 outputs the selected prediction vector mvpLX to the addition unit 3038.

  Note that a 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) within a predetermined range from the decoding target PU. The adjacent PU includes a PU that is spatially adjacent to the decoding target PU, for example, the left PU and the upper PU, and an area that is temporally adjacent to the decoding target PU, for example, the same position as the decoding target PU. It includes areas obtained from prediction parameters of PUs with different times.

  The adding unit 3038 adds the prediction vector mvpLX input from the AMVP prediction parameter deriving unit 3032 and the difference vector mvdLX input from the inter prediction parameter decoding control unit 3031 to calculate a motion vector mvLX. The adding unit 3038 outputs the calculated motion vector mvLX to the predicted image generation unit 308 and the prediction parameter memory 307.

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

(Motion compensation)
The motion compensation unit 3091 receives the reference picture index refIdxLX from the reference picture memory 306 based on the inter prediction parameters (prediction list utilization flag predFlagLX, reference picture index refIdxLX, motion vector mvLX) input from the inter prediction parameter decoding unit 303. In the reference picture RefX specified in (2), an interpolation image (motion compensation image predSamplesLX) is generated by reading out a block at a position shifted by the motion vector mvLX, starting from the position of the decoding target PU. Here, when the accuracy of the motion vector mvLX is not integer accuracy, a motion compensation image is generated by applying a filter for generating a pixel at a decimal position called a motion compensation filter.

(Weight prediction)
The weight prediction unit 3094 generates a prediction image of the PU by multiplying the input motion compensation image predSamplesLX by a weight coefficient. When one of the prediction list use flags (predFlagL0 or predFlagL1) is 1 (in the case of single prediction) and the weight prediction is not used, the input motion compensated image predSamplesLX (LX is L0 or L1) is represented by the number of pixel bits bitDepth The following equation is processed to match

predSamples [x] [y] = Clip3 (0, (1 << bitDepth)-1, (predSamplesLX [x] [y] + offset1) >> shift1)
Here, shift1 = 14−bitDepth, offset1 = 1 << (shift1-1).
When both of the reference list use flags (predFlagL0 and predFlagL1) are 1 (in the case of bi-prediction BiPred) and weight prediction is not used, the input motion compensation images predSamplesL0 and predSamplesL1 are averaged and the number of pixel bits The following equation is processed to match

predSamples [x] [y] = Clip3 (0, (1 << bitDepth)-1, (predSamplesL0 [x] [y] + predSamplesL1 [x] [y] + offset2) >> shift2)
Here, shift2 = 15-bitDepth, offset2 = 1 << (shift2-1).

(Modification of merge candidate derivation unit 30361)
Here, modified examples of the merge candidate derivation unit 30361 will be described with reference to FIGS. 8 and 14 to 16. In this modification, the merge prediction parameter derivation unit 3036 refers to at least one of a decoded block (CU or PU) adjacent to the prediction target block and a decoded block at a position away from the prediction target block. And Then, merge candidate derivation unit 30361 derives a merge candidate using the motion information (motion vector and reference picture index refIdxLX) of the reference block.

  However, the merge candidate deriving unit 30361 sets the motion information as a merge candidate only when the following condition is satisfied for a block at a position away from the prediction target block. Specifically, a block in which motion information is used as a merge candidate is such that at least one of a vertical distance and a horizontal distance from a boundary of a coding tree unit (CTU) including a prediction target block is a predetermined value or less. Limited to a certain block.

  That is, the inter prediction image generation unit 309 generates a prediction image of the target block with reference to the following block motion information among the blocks that are not adjacent to the target block. The block whose motion information is referred to by the inter prediction image generation unit 309 is a block in which at least one of the distance in the vertical direction and the distance in the horizontal direction from the boundary of the coding tree unit including the target block is a predetermined value or less. is there.

  According to the above configuration, the motion information of blocks that are more than a predetermined distance away from the CTU boundary including the target block is not referred to in the merging candidate derivation.

  For example, in merge prediction, motion information of blocks that are more than a predetermined distance from the CTU boundary can be excluded from merge candidates. The motion information of the block included in the CTU different from the CTU including the prediction target block is not stored in the internal memories of the image decoding device 31 and the image encoding device 11. Therefore, the number of motion information of blocks that are separated from the CTU boundary by a predetermined distance is included in the merge candidates. Therefore, external memory access in the image decoding device 31 and the image encoding device 11 is reduced. Therefore, it is possible to suppress an increase in the memory band in the image decoding device 31 and the image encoding device 11.

(Configuration of merge candidate derivation unit 30361)
FIG. 8 is a schematic diagram illustrating an example of the configuration of the merge candidate derivation unit 30361 according to the present modification.

  The merge candidate derivation unit 30361 includes a spatial merge candidate derivation unit 303611, and the spatial merge candidate derivation unit 303611 includes an availability determination unit 3036111.

  The availability determination unit 3036111 determines whether to apply the motion information (motion vector, reference picture index refIdxLX, etc.) of the decoded block at a position away from the prediction target block as a spatial merge candidate. A detailed determination example of the availability determination unit 3036111 will be described later.

  If the availability determination unit 3036111 determines to apply the motion information of the decoded block as a spatial merge candidate, it sets availableFlagP to 1. When availableFlagP is 1, the spatial merge candidate derivation unit 303611 stores the motion information of the decoded block in the merge candidate storage unit 30363 as a spatial merge candidate.

  If the availability determination unit 3036111 determines that the motion information of the decoded block is not applied as a spatial merge candidate, it sets availableFlagP to 0. When availableFlagP is 0, the spatial merge candidate derivation unit 303611 does not set the motion information of the decoded block as a spatial merge candidate.

(Judgment example 1 of availability judgment unit 3036111)
Here, an example of determination by the availability determination unit 3036111 will be described with reference to FIG. FIG. 14 is a schematic diagram illustrating an example of determination by the availability determination unit 3036111.

  In this example, the availability determination unit 3036111 determines motion information of a block whose vertical distance from a CTU boundary including the prediction target CU is a predetermined value or less as a spatial merge candidate.

  As shown in FIG. 14, the upper left coordinates of the CTU including the prediction target block are (xCTU, yCTU). Further, the coordinates of a block for determining whether or not the availability determination unit 3036111 uses the spatial merge candidate are (xNbP, yNbP).

  When the y coordinate (yNbP) of the block to be determined satisfies the following condition, the availability determination unit 3036111 determines the motion information of the block as a spatial merge candidate.

  Condition: The value of the y coordinate set above the y coordinate of the upper left coordinate of the CTU including the prediction target block by a predetermined value (K) or lower than that. For example, in the example shown in FIG. 14, the positions of the blocks A, A1, A2, B, B1, C, C1, D, D1, D2, E, and E1 are predetermined from the position indicated by the y coordinate of the upper left coordinates of the CTU. It is located below the value of the y coordinate set above by the value (K). Therefore, the motion information of the block is determined as a spatial merge candidate.

  In addition, the availability determination unit 3036111 uses the y-coordinate of the y-coordinate that is set by a predetermined value (K) above the position indicated by the y-coordinate of the upper-left coordinate of the CTU that includes the prediction target block. If it is located above the value, the motion information of the block is not determined as a spatial merge candidate. For example, in the example shown in FIG. 14, the positions of the blocks B2, C2, and E2 are higher than the value of the y coordinate set by a predetermined value (K) above the position indicated by the y coordinate of the upper left coordinate of the CTU. To position. Therefore, the motion information of the block is not determined as a spatial merge candidate.

The above determination can be expressed by the following equation.
availableFlagP = (yNbP <yCTU-K)? 0: 1
if (availableFlagP)
{
mvLXP = MvLX [xNbP] [yNbP]
refIdxLXP = RefIdxLX [xNbP] [yNbP]
predFlagLXP = PredFlagLX [xNbP] [yNbP]

mergeCandList [i ++] = P
}
Note that the availability determination unit 3036111 may determine that the motion information of a block whose horizontal distance from the boundary of the coding tree unit (CTU) to which the prediction target CU belongs is a predetermined value or less is applied as a spatial merge candidate. .

  The predetermined value K is preferably a coordinate value of 1 to 16.

In addition, you may refer in coarse units, such as 8x8 and 16x16 units, as follows. That is, the reference position may be thinned out as follows (the same applies to the subsequent configurations).
if (availableFlagP)
{
xNbP = (xNbP >> shiftL) << shiftL)
yNbP = (yNbP >> shiftK) << shiftK)
mvLXP = MvLX [xNbP] [yNbP]
refIdxLXP = RefIdxLX [xNbP] [yNbP]
predFlagLXP = PredFlagLX [xNbP] [yNbP]
mergeCandList [i ++] = P
}
Here, shiftL and shiftK are shift values for thinning out the coordinates, and 3, 4, 5, etc. can be used.

(Determination example 2 of availability determination unit 3036111)
Next, another example of the determination by the availability determination unit 3036111 will be described with reference to FIG. FIG. 15 is a schematic diagram illustrating another example of the determination by the availability determination unit 3036111.

  In this example, the availability determination unit 3036111 has a block whose vertical distance from the boundary of the coding tree unit (CTU) including the prediction target CU is a predetermined value or less and whose horizontal distance is a predetermined value or less. The motion information is determined as a spatial merge candidate. .

  As shown in FIG. 15, the upper left coordinates of the CTU including the prediction target block are (xCTU, yCTU). Further, the coordinates of a block for determining whether or not the availability determination unit 3036111 uses the spatial merge candidate are (xNbP, yNbP).

  The availability determination unit 3036111 determines that the motion information of the block is a spatial merge candidate when the determined block satisfies both the following conditions (1) and (2). Condition (1): Whether the y-coordinate (yNbP) of the block to be determined is a y-coordinate value set by a predetermined value (K) above the position indicated by the y-coordinate of the upper left coordinate of the CTU that includes the prediction target block Located below it. Condition (2): Whether the x coordinate (xNbP) of the block to be determined is the x coordinate value set to the left by a predetermined value (L) from the position indicated by the x coordinate of the upper left coordinate of the CTU including the prediction target block Located to the right of it.

  In the example shown in FIG. 15, the blocks A, A1, B, B1, C, C1, D, D1, E, and E1 satisfy both the above-described condition (1) and condition (2). Therefore, the motion information of the block is determined as a spatial merge candidate. In the example shown in FIG. 15, the blocks A2, B2, C2, D2, and E2 do not satisfy at least one of the above condition (1) and condition (2). Therefore, the motion information of the block is not determined as a spatial merge candidate.

The above determination can be expressed by the following equation.
availableFlagP = (yNbP <yCTU-K) || (xNbP <xCTU-L)? 0: 1
if (availableFlagP)
{
mvLXP = MvLX [xNbP] [yNbP]
refIdxLXP = RefIdxLX [xNbP] [yNbP]
predFlagLXP = PredFlagLX [xNbP] [yNbP]

mergeCandList [i ++] = P
}
The predetermined values K and L are preferably coordinate values of 1 to 16.

(Example of block to be determined by availability determination unit 3036111)
Next, an example of a block that is a determination target of the availability determination unit 3036111 will be described with reference to FIG. FIG. 16 is a schematic diagram illustrating an example of a block to be determined by the availability determination unit 3036111. Specifically, FIG. 16 is a diagram illustrating an example of a block that is a determination target of the availability determination unit 3036111 in the determination example 1 described above. In this example, blocks determined by the availability determination unit 3036111 are thinned out. That is, the availability determination unit 3036111 performs the above determination on a block located at the coordinates of a coarse unit (for example, a unit of 8x8 or 16x16). For example, only one block is determined by the availability determination unit 3036111 for each area indicated by a broken line in FIG.

  The above determination can be expressed by the following equation. That is, the distance from the CTU boundary may be determined using the coordinates after thinning ((yNbP >> shiftK) << shiftK).

if ((yNbP >> shiftK) <<shiftK)> = yCTU-K)
{
xNbP = (xNbP >> shiftL) << shiftL)
yNbP = (yNbP >> shiftK) << shiftK)

mvLXP = MvLX [xNbP] [yNbP]
refIdxLXP = RefIdxLX [xNbP] [yNbP]
predFlagLXP = PredFlagLX [xNbP] [yNbP]
}
By deciding in this way, in the derivation of the spatial merge candidate that performs the thinning of the reference position, the position before thinning (xNb, yNb) is a predetermined range when viewed from the target CTU, even though it is within a predetermined range. The problem that the position ((xNbP >> shiftL) << shiftL), (yNbP >> shiftK) << shiftK)) exceeds the predetermined range is eliminated.

  In the above example, the example of the block that is the determination target of the availability determination unit 3036111 in the determination example 1 of the availability determination unit 3036111 is shown. However, in the determination example 2, the block that is the determination target is the same as this example. May be.

(Change of thinning amount of reference position)
In addition, the availability determination unit 3036111 uses the y-coordinate of the y-coordinate that is set by a predetermined value (K) above the position indicated by the y-coordinate of the upper-left coordinate of the CTU that includes the prediction target block. The thinning-out amount of the coordinates referring to the motion information may be changed depending on whether the position is lower than the value. For example, when the position of the reference position (xNbP, yNbP) of the spatial merge candidate is above a predetermined value as viewed from the position of the target CTU, the reference position may be thinned by the thinning amount (shiftK, shiftL). Here, a determinationFlag indicating whether or not the reference position exceeds a predetermined range as viewed from the target CTU is derived, and if the reference position is far from the predetermined position, thinning is performed.
decimationFlag = (yNbP <yCTU-K)? 0: 1
if (decimationFlag)
{
xNbP = (xNbP >> shiftL) << shiftL)
yNbP = (yNbP >> shiftK) << shiftK)
}
mvLXP = MvLX [xNbP] [yNbP]
refIdxLXP = RefIdxLX [xNbP] [yNbP]
predFlagLXP = PredFlagLX [xNbP] [yNbP]
Here, shiftL and shiftK are shift values for thinning out the coordinates, and 3, 4, 5, etc. can be used.

  Example 1: When K = 1 and shiftL = shiftK = 2, blocks that are in contact with the CTU boundary are not thinned out, and blocks that are not in contact with the CTU boundary are thinned out to 8 × 8 units.

  Example 2: When K = 1, shiftL = 2, and shiftK = 1, blocks that are in contact with the CTU boundary are not thinned out, and blocks that are not in contact with the CTU boundary are thinned out to 8 × 4 units.

  Example 3: When K = 1, shiftL = 1, and shiftK = 2, blocks that are in contact with the CTU boundary are not thinned out, and blocks that are not in contact with the CTU boundary are thinned out to 4 × 8 units.

  Further, for example, the thinning amount may be changed depending on whether or not the position of the reference position (xNbP, yNbP) of the spatial merge candidate is above a predetermined value as viewed from the position of the target CTU. A decisionFlag indicating whether or not the reference position exceeds the predetermined range from the target CTU is derived. If the flag of the decisionFlag is false (normal), the first shift amount shiftL1, shiftK1 is used, and the flag is true In this case, a second shift amount (shiftL2, shiftK2) larger than the first shift amount may be used.

shiftL = decimationFlag? shiftL2: shiftL1
shiftK = decimationFlag? shiftK2: shiftK1
xNbP = (xNbP >> shiftL) << shiftL)
yNbP = (yNbP >> shiftK) << shiftK)
Where shiftL2> shiftL1, shiftK2> shiftK1. For example, shiftL2 = shiftK2 = 3 and shiftL2 = shiftK2 = 2 may be used.

Note that both of the CTU coordinates (xCTU, yCTU) including the target block may be used to derive the decisionFlag as in the following equation.
decimationFlag = (yNbP <yCTU-K) || (xNbP <xCTU-L)? 0: 1
Note that the coordinates of points to be referred to when deriving the decisionFlag may be thinned out.

decimationFlag = ((yNbP >> shiftK) << shiftK) <yCTU-K? 0: 1
Alternatively, the following may be used.

decimationFlag = (((yNbP >> shiftK) << shiftK) <yCTU-K) || (((xNbP >> shiftL) << shiftL) <yCTU-L)? 0: 1
According to the above configuration, when referring to the motion information at a position away from the target CTU, the reference position is thinned out, so that the motion information at a position away from the target CTU can be roughly stored. Thereby, the memory size for storing motion information can be reduced.

(Configuration of image encoding device)
Next, the configuration of the image encoding device 11 according to the present embodiment will be described. FIG. 4 is a block diagram illustrating a configuration of the image encoding device 11 according to the present embodiment. The image encoding device 11 includes a predicted image generation unit 101, a subtraction unit 102, a transform / quantization unit 103, an entropy encoding unit 104, an inverse quantization / inverse transform unit 105, an addition unit 106, a loop filter 107, and a prediction parameter memory. (Prediction parameter storage unit, frame memory) 108, reference picture memory (reference image storage unit, frame memory) 109, encoding parameter determination unit 110, and prediction parameter encoding unit 111. The prediction parameter encoding unit 111 includes an inter prediction parameter encoding unit 112 and an intra prediction parameter encoding unit 113.

  For each picture of the image T, the predicted image generation unit 101 generates a predicted image P of the prediction unit PU for each encoding unit CU that 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 encoding unit 111.

  The predicted image generation unit 101 has the same operation as the predicted image generation unit 308 already described. For example, FIG. 6 is a schematic diagram illustrating a configuration of an 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. Since the motion compensation unit 10111 and the weight prediction unit 10112 have the same configurations as the motion compensation unit 3091 and the weight prediction unit 3094 described above, description thereof is omitted here.

  The predicted image generation unit 101 generates a predicted image P of the PU based on the pixel value of the reference block read from the reference picture memory, using the parameter input from the prediction parameter encoding 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, and generates a residual signal. The subtraction unit 102 outputs the generated residual signal to the transform / quantization unit 103.

  The transformation / quantization unit 103 performs frequency transformation on the residual signal input from the subtraction unit 102 and calculates a transformation coefficient. The transform / quantization unit 103 quantizes the calculated transform coefficient to obtain a quantized coefficient. The transform / quantization unit 103 outputs the obtained quantization coefficient to the entropy coding unit 104 and the inverse quantization / inverse transform unit 105.

  The entropy encoding unit 104 receives the quantization coefficient from the transform / quantization unit 103 and the encoding parameter from the prediction parameter encoding unit 111. Examples of input encoding parameters include 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 encoding unit 104 generates an encoded stream Te by entropy encoding the input quantization coefficient and encoding parameter, and outputs the generated encoded stream Te to the outside.

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

  The addition unit 106 adds the signal value of the prediction 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 conversion unit 105 for each pixel, and performs decoding. Generate an image. The adding unit 106 stores the generated decoded image in the reference picture memory 109.

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

  The prediction parameter memory 108 stores the prediction parameter generated by the encoding parameter determination unit 110 at a predetermined position for each picture and CU to be encoded.

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

  The encoding parameter determination unit 110 selects one set from among a plurality of sets of encoding parameters. The encoding parameter is a parameter to be encoded that is generated in association with the above-described prediction parameter or the prediction parameter. The predicted image generation unit 101 generates a predicted image P of the PU using each of these encoding parameter sets.

  The encoding parameter determination unit 110 calculates a cost value indicating the amount of information and the encoding error for each of the plurality of sets. The cost value is, for example, the sum of a code amount and a square error multiplied by a coefficient λ. The code amount is the information amount of the encoded stream Te obtained by entropy encoding the quantization error and the encoding parameter. The square error is the sum between pixels regarding the square value of the residual value of the residual signal calculated by the subtracting unit 102. The coefficient λ is a real number larger than a preset zero. The encoding parameter determination unit 110 selects a set of encoding parameters that minimizes the calculated cost value. As a result, the entropy encoding unit 104 outputs the selected set of encoding parameters to the outside as the encoded stream Te, and does not output the set of unselected encoding parameters. The encoding parameter determination unit 110 stores the determined encoding parameter in the prediction parameter memory 108.

  The prediction parameter encoding unit 111 derives a format for encoding from the parameters input from the encoding parameter determination unit 110 and outputs the format to the entropy encoding unit 104. Deriving the format for encoding is, for example, deriving a difference vector from a motion vector and a prediction vector. Also, the prediction parameter encoding unit 111 derives parameters necessary for generating a prediction image from the parameters input from the encoding parameter determination unit 110 and outputs the parameters to the prediction image generation unit 101. The parameter necessary for generating the predicted image is, for example, a motion vector in units of sub-blocks.

  The inter prediction parameter encoding unit 112 derives an inter prediction parameter such as a difference vector based on the prediction parameter input from the encoding parameter determination unit 110. The inter prediction parameter encoding unit 112 derives parameters necessary for generating a prediction image to be output to the prediction image generating unit 101, and an inter prediction parameter decoding unit 303 (see FIG. 5 and the like) derives inter prediction parameters. Some of the configurations are the same as the configuration to be performed. The configuration of the inter prediction parameter encoding unit 112 will be described later.

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

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

  The inter prediction parameter encoding unit 112 includes an inter prediction parameter encoding control unit 1121, an AMVP prediction parameter derivation unit 1122, a subtraction unit 1123, a sub-block prediction parameter derivation unit 1125, a merge prediction parameter derivation unit 1126, and a partition mode derivation (not shown). , A merge flag deriving unit, an inter prediction identifier deriving unit, a reference picture index deriving unit, a vector difference deriving unit, and the like.

  In particular, the merge prediction parameter derivation unit 1126 may be configured to correspond to the merge prediction parameter derivation unit 3036 described above. That is, the merge prediction parameter deriving unit 1126 may include a configuration corresponding to the merge candidate deriving unit 30361, the spatial merge candidate deriving unit 303611, and the availability determining unit 3036111.

  The partition mode deriving unit, the merge flag deriving unit, the inter prediction identifier deriving unit, the reference picture index deriving unit, and the vector difference deriving unit are respectively the PU partition mode part_mode, the merge flag merge_flag, the inter prediction identifier inter_pred_idc, the reference picture index refIdxLX, and the difference vector Derives mvdLX. The inter prediction parameter encoding unit 112 outputs the motion vector (mvLX, subMvLX), the reference picture index refIdxLX, the PU partition mode part_mode, the inter prediction identifier inter_pred_idc, or information indicating these to the prediction image generating unit 101.

  Further, the inter prediction parameter encoding unit 112 entropy PU partition 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. The data is output to the encoding unit 104.

  The inter prediction parameter coding control unit 1121 includes a merge index deriving unit 11211 and a vector candidate index deriving unit 11212. The merge index derivation unit 11211 compares the motion vector and reference picture index input from the encoding parameter determination unit 110 with the motion vector and reference picture index of the merge candidate PU read from the prediction parameter memory 108, and performs merge An index merge_idx is derived and output to the entropy encoding unit 104. A merge candidate is a reference PU (for example, a reference PU that touches the lower left end, upper left end, and upper right end of the encoding target block) within a predetermined range from the encoding target CU to be encoded. The PU has been processed. The vector candidate index deriving unit 11212 derives a prediction vector index mvp_LX_idx.

  When the encoding parameter determination unit 110 determines to use the subblock prediction mode, the subblock prediction parameter derivation unit 1125 selects one of spatial subblock prediction, temporal subblock prediction, and matching motion derivation according to the value of subPbMotionFlag. A motion vector and a reference picture index for sub-block prediction are derived. As described in the description of the image decoding apparatus, the motion vector and the reference picture index are derived by reading out the motion vector and the reference picture index such as the adjacent PU and the reference picture block from the prediction parameter memory 108.

  The AMVP prediction parameter derivation unit 1122 has the same configuration as the AMVP prediction parameter derivation unit 3032 (see FIG. 12).

  The subtraction 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 encoding unit 104.

  In addition, a part of the image encoding device 11 and the image decoding device 31 in the above-described embodiment, for example, the entropy decoding unit 301, the prediction parameter decoding unit 302, the loop filter 305, the predicted image generation unit 308, the inverse quantization / inverse transformation. Unit 311, addition unit 312, predicted image generation unit 101, subtraction unit 102, transform / quantization unit 103, entropy encoding unit 104, inverse quantization / inverse transform unit 105, loop filter 107, encoding parameter determination unit 110, The prediction parameter encoding unit 111 may be realized by a computer. In that case, the program for realizing the control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by a computer system and executed. Here, the “computer system” is a computer system built in either the image encoding device 11 or the image decoding device 31 and includes hardware such as an OS and peripheral devices. The “computer-readable recording medium” refers to a storage device such as a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a hard disk built in a computer system. Furthermore, the “computer-readable recording medium” is a medium that dynamically holds a program for a short time, such as a communication line when 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 inside a computer system serving as a server or a client may be included and a program that holds a program for a certain period of time. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  Moreover, you may implement | achieve part or all of the image coding apparatus 11 in the embodiment mentioned above, and the image decoding apparatus 31 as integrated circuits, such as LSI (Large Scale Integration). Each functional block of the image encoding device 11 and the image decoding device 31 may be individually made into a processor, or a part or all of them may be integrated into a processor. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. Further, in the case where an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology may be used.

  As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the scope of the present invention. It is possible to

(Second Embodiment)
(Type of block division)
A description will be given of division of a coding node (CN) according to the present embodiment. FIG. 17 is a diagram illustrating division of coding nodes (CN, blocks) in the image decoding device 31. In the present embodiment, the image decoding device 31 divides the coding tree unit or CN into quadtree division (QT division), binary tree / binary tree division (BT division), or triple tree / ternary tree division (TT division). ), And is divided into coding units (CU: Coding Units) which are basic units of the coding process. FIG. 17A shows QT division of a block. FIG. 17B shows an example in which the block is divided into BT in the horizontal direction (HOR). FIG. 17C shows an example in which the block is divided into BT in the vertical direction (VER). As shown in FIGS. 17B and 17C, the BT division divides the sides of the block into one-to-one correspondence. FIG. 17D shows an example in which the block is not divided. FIG. 17E shows an example in which a block is TT-divided in the horizontal direction (HOR). FIG. 17F shows an example in which a block is TT-divided in the vertical direction (VER). In the TT division, the divided side of the block is divided into 1 to 2 to 1.

  In the present specification, regarding the division, the terms “horizontal” and “vertical” refer to the direction of the dividing line. Accordingly, “horizontal division” and “horizontal division” mean division by a horizontal boundary line, that is, division into two blocks, upper and lower. “Vertical division” and “vertical division” mean division by a vertical boundary line, that is, division into two blocks, left and right.

  Although not exemplified in this specification, there is another terminology. That is, the horizontal division of the present specification is divided into two or more blocks in which a certain block is arranged in the vertical direction, and may be referred to as split vertically. In addition, the vertical division of the present specification may be called split horizontally because a certain block is divided into two or more blocks arranged in the horizontal direction. It should be noted that the description of vertical division in the above other terminology may mean horizontal division in the present specification (or vice versa). In this case, the term is appropriately read in the meaning of the term.

  FIG. 18 is a diagram illustrating tree-type signaling performed by the image decoding device 31. As illustrated in FIG. 18, the image decoding device 31 performs RT (region tree) division by repeating quadtree division on CTU or CN. Thereafter, when there is a PT (Partition Tree, multi tree) partitioning (BT partitioning or TT partitioning) flag, the image decoding device 31 determines whether to divide the block horizontally or vertically. Thereafter, the image decoding device 31 determines whether the division is BT division or TT division, and divides the block.

(Configuration of Image Decoding Device 31)
FIG. 19 shows a configuration of the image decoding device 31 according to the present embodiment. FIG. 19 is a block diagram illustrating a main configuration of the image decoding device 31 according to the present embodiment. In FIG. 19, in order to simplify the drawing, illustration of some members is omitted. For convenience of explanation, members having the same functions as those shown in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted.

  As illustrated in FIG. 19, the image decoding device 31 includes a decoding module 9, a CN information decoding unit 10 (decoding unit), a predicted image generation unit 308, an inverse quantization / inverse DCT unit 311, a reference picture memory 306, and an addition unit 312. A loop filter 305, a header decoding unit 19, and a CU decoding unit 20. Although not shown in FIG. 19, the image decoding device 31 according to the present embodiment includes a sub-block prediction parameter deriving unit 3037 as shown in FIG. Further, the sub-block prediction parameter deriving unit 3037 according to this embodiment includes a matching motion deriving unit 30373 as shown in FIG. The CU decoding unit 20 further includes a PU information decoding unit 12 and a TT information decoding unit 13, and the TT information decoding unit 13 further includes a TU decoding unit 22.

  The decoding module 9 performs a decoding process for decoding a syntax value from binary data. More specifically, the decoding module 9 decodes and decodes a syntax value encoded by an entropy encoding method such as CABAC based on encoded data and syntax type supplied from the supplier. Returns the syntax value to the supplier.

  In the example shown below, the sources of encoded data and syntax type are the CN information decoding unit 10 and the CU decoding unit 20 (PU information decoding unit 12 and TT information decoding unit 13).

  The header decoding unit 19 decodes the VPS (video parameter set), SPS, PPS, and slice header of the encoded data input from the image encoding device 11.

  The CN information decoding unit 10 uses the decoding module 9 to perform decoding processing of the encoding tree unit and the encoding node on the encoded data input from the image encoding device 11. Specifically, the CN information decoding unit 10 decodes the CTU information and the CN information from the encoded data according to the following procedure.

  First, the CN information decoding unit 10 uses the decoding module 9 to decode the tree unit header CTUH from the CTU information included in the CTU. Next, the CN information decoding unit 10 determines, from the CN information included in the CN, a QT division flag indicating whether the target CN is QT-divided, and a PT division flag indicating whether the target CN is BT-divided or TT-divided , A division direction flag (mt_dir_flag) indicating a division direction of BT division or TT division, a split mode selection flag (split_mt_flag) indicating a division method of PT division (BT division or TT division), a QT division flag and a PT division flag The target CN is recursively divided and decoded until no further division is notified. Finally, the tree unit footer CTUF is decoded from the CTU information.

  The tree unit header CTUH and the tree unit footer CTUF include coding parameters referred to by the image decoding device 31 in order to determine a decoding method of the target coding tree unit. In addition to the QT division flag, the PT division flag, the division direction flag, and the division mode selection flag, the CN information may include parameters applied in the target CN and the lower or higher encoding node.

  The CU decoding unit 20 includes a PU information decoding unit 12 and a TT information decoding unit 13, and decodes PUI information and TTI information of the lowest coding node CN (ie, CU).

  In the PU information decoding unit 12, PU information (merge flag (merge_flag), merge index (merge_idx), prediction motion vector index (mvp_idx), reference image index (ref_idx), inter prediction identifier (inter_pred_idc), difference vector (mvd) of each PU ) And the OBMC flag OBMC_flag) using the decoding module 9.

  The TT information decoding unit 13 decodes each TTI (TU division flag split_transform_flag, CU residual flag cbf_cb, cbf_cr, cbf_luma, etc., and TU) using the decoding module 9.

  Further, the TT information decoding unit 13 includes a TU decoding unit 22. The TU decoding unit 22 decodes the QP update information (quantization correction value) when a residual is included in the TU. The QP update information is a value indicating a difference value from the quantization parameter predicted value qPpred, which is a predicted value of the quantization parameter QP. The TU decoding unit 22 decodes the quantized prediction residual (residual_coding).

  The operation of CN information decoding by the CN information decoding unit 10 will be described with reference to FIG. FIG. 20 is a flowchart for explaining the QT information decoding process and the BT / TT information decoding process of the CN information decoding unit 10 according to this embodiment. FIGS. 22 and 23 are diagrams showing an example of syntax related to the QT information decoding process. When the step numbers shown in FIG. 20 and the numbers given to the syntax configurations shown in FIGS. 22 and 23 are the same, they indicate corresponding processes. For example, S1421 in FIG. 20 and SYN1421 in FIG. 23 indicate corresponding processes.

  In CN information decoding by the CN information decoding unit 10, QT information decoding and BT information or TT information (BT / TT information) decoding are performed. First, QT information decoding by the CN information decoding unit 10 will be described in order.

  First, the CN information decoding unit 10 decodes CN information from encoded data, and recursively decodes a coding node (CN). Specifically, the CN information decoding unit 10 decodes the QT information and decodes the target encoding tree coding_quadtree (x0, y0, log2CbSize, cqtDepth). Note that x0 and y0 are the upper left coordinates of the target encoding node, log2CbSize is the CN size that is the size of the encoding node, and the logarithmic CN size that is the logarithm of 2 (for example, the CN size is 64, 128, 256). If so, 6, 7, 8). cqtDepth is a CN hierarchy (QT depth) indicating a hierarchy of coding nodes.

  The CN information decoding unit 10 determines whether or not the decoded CN information has a QT division flag. Specifically, the CN information decoding unit 10 determines whether or not the logarithmic CN size log2CbSize is larger than a logarithmic value MinCbLog2SizeY of a predetermined minimum CN size. If the logarithmic CN size log2CbSize is larger than MinCbLog2SizeY (YES in S1411), it is determined that there is a QT division flag, and the process proceeds to S1421. In other cases (NO in S1411), the process proceeds to S1422 (S1411).

  When it is determined that the logarithmic CN size log2CbSize is larger than MinCbLog2SizeY, the CN information decoding unit 10 decodes a QT split flag (split_cu_flag) that is a syntax element (S1421).

  In other cases (logarithmic CN size log2CbSize is equal to or smaller than MinCbLog2SizeY), that is, when the QT split flag split_cu_flag does not appear in the encoded data, the CN information decoding unit 10 omits decoding of the QT split flag split_cu_flag from the encoded data The QT division flag plit_cu_flag is derived as 0 (S1422).

  When the QT division flag split_cu_flag is other than 0 (= 1) (YES in S1431), the CN information decoding unit 10 moves down one layer and repeats the processes in and after step S1411. In other cases (YES in 1431, QT split flag split_cu_flag is 0), the process proceeds to BT / TT information decoding processing.

The CN information decoding unit 10 performs QT division. Specifically, the CN information decoding unit 10 has the logarithmic CN size log2CbSize−1 at the positions (x0, y0), (x1, y0), (x0, y1), (x1, y1) of the CN hierarchy cqtDepth + 1. Four encoded nodes CN are decoded (S1441).
coding_quadtree (x0, y0, log2CbSize-1, cqtDepth + 1)
coding_quadtree (x1, y0, log2CbSize-1, cqtDepth + 1)
coding_quadtree (x0, y1, log2CbSize-1, cqtDepth + 1)
coding_quadtree (x1, y1, log2CbSize-1, cqtDepth + 1)
That is, the blocks to be decoded are scanned in the raster scan order.

Here, x0, y0 are the upper left coordinates of the target encoding node, and x1, y1 are (x0, y0) plus 1/2 the logarithmic CN size (1 << log2CbSize) as shown in the following formula: Is derived.
x1 = x0 + (1 << (log2CbSize-1))
y1 = y0 + (1 << (log2CbSize-1))
Note that << indicates a left shift. 1 << N is equivalent to 2 raised to the Nth power (the same applies hereinafter). Similarly, >> indicates a right shift.

Then, the CN information decoding unit 10 adds 1 to the CN layer cqtDepth indicating the layer of the encoding node, and subtracts the logarithmic CN size log2CbSize, which is a logarithmic value of the encoding unit size, by 1 (CN size is 1/2). And update.
cqtDepth = cqtDepth + 1
log2CbSize = log2CbSize-1
The CN information decoding unit 10 continues the QT information decoding started from S1411 using the updated upper left coordinate, logarithmic CN size, and CN hierarchy even in the lower encoding node.

(Flow of QT information decoding process of CN information decoding unit 10)
Next, an outline of the BT / TT information decoding process performed by the CN information decoding unit 10 will be described with reference to FIG. FIG. 21 is a flowchart showing an outline of an example of the flow of the BT / TT information decoding process of the CN information decoding unit 10. 24A to 24C are diagrams illustrating an example of syntax related to the BT / TT information decoding process.

  When the QT split flag split_cu_flag is 0 in S1431, the CN information decoding unit 10 determines whether or not the target block can be BT or TT split based on the size of the target block and the like, and the PT split flag (MT split flag) ) (S1501: PT division flag determination). The PT division flag is a flag indicating whether or not the target block is subjected to BT division or TT division. If decoding of the PT division flag is “necessary” (YES in S1501), the CN information decoding unit 10 decodes the PT division flag (S1502). Subsequently, the CN information decoding unit 10 determines whether or not the decoded PT division flag is 0 (S1503). If the PT division flag is 0 (NO in S1503), the process ends. When the PT division flag is other than 0 (YES in S1503), the CN information decoding unit 10 determines whether or not it is uniquely determined by the restriction on the division of the block in which the division direction of the division target block is set. Then, it is determined whether or not the division direction flag needs to be decoded (S1504: division direction flag determination). When decoding of the division direction flag is “necessary” (when the division direction is not uniquely determined, etc.) (YES in S1504), the CN information decoding unit 10 decodes the division direction flag (S1505) and determines the division direction. The process continues to S1506. If decoding of the division direction flag is “unnecessary” (eg, the division direction is uniquely determined) (NO in S1504), the CN information decoding unit 10 does not decode the division direction flag, and the process continues to S1506. In S1506, the CN information decoding unit 10 determines whether or not the division mode is uniquely determined by the division limitation of the block in which the division mode (TT division, BT division) of the division target block is set, and the like. It is determined whether or not the division mode selection flag needs to be decoded (S1506: division mode selection flag determination). When decoding of the division mode selection flag is “necessary” (when the division mode is not uniquely determined or the like) (YES in S1506), the CN information decoding unit 10 decodes the division mode selection flag (S1507), and sets the division mode. The decision is made and processing continues to S1508. When decoding of the split mode selection flag is “unnecessary” (when the split mode is uniquely determined, etc.) (NO in S1506), the CN information decoding unit 10 does not decode the split mode selection flag, Continue to S1508. Subsequently, in S1508, the CN information decoding unit 10 divides according to the direction in which the division target block is determined and the determined division mode (S1508).

The syntax corresponding to the flowchart of FIG. 21 is shown in FIGS. 24A to 24C. Among them, for example, the horizontal TT division can be expressed by the following equation as shown in FIG. 24B.
coding_ternary_tree (x0, y0, log2CbWidth-2, log2CbHeight, cqtDepth + 1)
coding_ternary_tree (x1, y0, log2CbWidth-1, log2CbHeight, cqtDepth + 1)
coding_ternary_tree (x2, y0, log2CbWidth-2, log2CbHeight, cqtDepth + 1)
Further, the BT division in the horizontal direction can be expressed by the following equation as shown in FIG. 24C.
coding_binary_tree (x0, y0, log2CbWidth-2, log2CbHeight, cqtDepth + 1)
coding_binary_tree (x1, y0, log2CbWidth-2, log2CbHeight, cqtDepth + 1)
The blocks decoded in the TT division and the BT division are scanned in the order of the blocks shown in the above formula.

  Subsequently, a loop process for repeatedly performing the BT / TT information decoding process on the block generated by the division is performed (S1509, S1510, S1511). When the loop process ends, the process ends.

(Template area setting in template matching)
As described in the first embodiment, the matching motion deriving unit (motion information deriving unit) 30373 derives a motion vector (motion information) in template matching. Specifically, the matching motion deriving unit 30373 derives a motion vector by matching the decoded region Temp_Cur (template) adjacent to the target block and the motion compensated image of the adjacent region Temp_L0 of the reference block on the reference picture. . Hereinafter, an example of setting a template area in template matching according to the present embodiment will be described. The configuration shown in each “example of template area setting” described below is intended to suppress setting of a pixel included in a block processed immediately before the target block as a template area for template matching. It is a configuration.

(Example 1 of template area setting in template matching)
The matching motion deriving unit 30373 according to this example does not set the pixel included in the block processed immediately before the target block as the template for template matching.

  According to the above configuration, the matching motion deriving unit 30373 derives a motion vector without setting the pixel included in the block to be decoded immediately before the target block as the template region. In other words, the image decoding device 31 can start the predicted image generation processing for the next block without waiting for the end of the decoding processing for the block processed immediately before. In the present embodiment, the target block may be a CU.

  Next, setting of a template area in template matching according to the present example will be described in detail with reference to FIGS. 25 to 27 are diagrams showing an example of a template area set by the matching motion deriving unit 30373 according to this example.

  The CTU shown in FIG. 25 to FIG. 27 is divided by the first QT division, and each block generated by the first QT division is further divided as follows. The upper left block generated by the first QT division is not divided. In the upper right block generated by the first QT division, vertical BT division is performed. The lower left block generated by the first QT division is subjected to the second QT division. The lower right block generated by the first QT division is subjected to horizontal TT division.

  In FIG. 25 to FIG. 27, a block with T is a target block to be subjected to template matching, and a block with P is a block (hereinafter referred to as a block to be decoded) immediately before the target block (T). It is called “Previous Block”). In addition, the filled area shown in FIGS. 25 to 27 is a template area set for the target block (T).

  FIG. 25A shows a template region when the upper left block generated by the first QT division is the target block.

  (B) and (c) of FIG. 25 show template regions when each block generated by further BT-dividing the upper right block generated by the first QT division in the vertical direction becomes the target block. ing.

  (A) to (d) of FIG. 26 show template regions in the case where each block generated by further QT-dividing the lower left block generated by the first QT division becomes the target block.

  (A) to (c) of FIG. 27 show template regions in the case where each block generated by further TT-dividing the lower right block generated by the first QT division in the horizontal direction becomes the target block. Show.

  In the first embodiment, the template region Temp_Cur includes a region adjacent to the upper side of the target block (sub block Cur_block) and a region adjacent to the left side of the target block.

  On the other hand, in this example, the template area is limited as follows.

  As shown in FIGS. 25B and 25C and FIGS. 26B and 26D, in this example, when the block adjacent to the left side of the target block is the immediately preceding block, the left side of the target block. The area adjacent to is not a template area. That is, when the block adjacent to the left side of the target block is the immediately preceding block, the region adjacent to the upper side of the target block is set as the template region.

  As shown in FIGS. 27B and 27C, when the block adjacent to the upper side of the target block is the immediately preceding block, the area adjacent to the upper side of the target block is not set as the template area. . That is, when the block adjacent to the upper side of the target block is the immediately preceding block, the area adjacent to the left side of the target block is set as the template area.

  In addition, as shown in FIGS. 25A, 26A and 26C, and FIG. 27A, if the block adjacent to the left and upper sides of the target block is not the immediately preceding block, the target block A region adjacent to the upper side and the left side is set as a template region.

  The matching motion deriving unit 30373 may determine whether or not to use the region adjacent to the upper side of the target block or the region adjacent to the left side of the target block as a template region as follows.

  When both of the following two conditions (1) and (2) are satisfied, the region adjacent to the left side of the target block overlaps with the immediately preceding block.

  Condition (1): The x coordinate value of the target block is equal to the x coordinate value of the immediately preceding block plus the width of the immediately preceding block.

  Condition (2): The value of the y coordinate of the target block is not less than the value of the y coordinate of the immediately preceding block and less than the value of the y coordinate of the immediately preceding block plus the height of the immediately preceding block.

  When both the conditions (1) and (2) are satisfied, the matching motion derivation unit 30373 determines that the region adjacent to the left side of the target block cannot be used as the template region. For example, the matching motion deriving unit 30373 sets leftAvail, which is a flag indicating whether or not an area adjacent to the left side of the target block can be used as a template area, to 0.

  If the target block coordinates are (xCU, yCU), the previous block coordinates are (xPrevCU, yPrevCU), and the previous block size (width, height) is (wPrev, hPrev), the above judgment is as follows: It can be shown as a formula of

leftAvail =! {(xCU == xPrevCU + wPrevCU) && (yPrevCU <= yCU) && (yCU <yPrevCU + hPrev)}
When both of the following two conditions (3) and (4) are satisfied, the area adjacent to the upper side of the target block overlaps with the immediately preceding block.

  Condition (3): The value of the y coordinate of the target block is equal to the value of the y coordinate of the immediately preceding block plus the height of the immediately preceding block.

  Condition (4): The x-coordinate value of the target block is equal to or greater than the x-coordinate value of the immediately preceding block and less than the value obtained by adding the width of the immediately preceding block to the x coordinate of the immediately preceding block.

  When both the conditions (3) and (4) are satisfied, the matching motion derivation unit 30373 determines that the area adjacent to the upper side of the target block cannot be used as the template area. For example, the matching motion deriving unit 30373 sets aboveAvail, which is a flag indicating whether or not an area adjacent to the upper side of the target block can be used as a template area, to 0 (unusable).

The above judgment can be expressed as the following equation.
aboveAvail =! {(yCU == yPrevCU + hPrevCU) && (xPrevCU <= xCU) && (xCU <xPrevCU + wPrev)}
When either leftAvail or aboveAvail is 1, the matching motion deriving unit 30373 derives the motion vector of the target block by matching using the derived template region. Note that the matching motion deriving unit 30373 derives the left and upper areas when leftAvail = aboveAvail = 1, the left area when leftAvail = 1, and the upper adjacent area when aboveAvail = 1 as a template area.

(Example 2 of template area setting in template matching)
The matching motion deriving unit 30373 according to this example sets a template region for template matching according to the index allocated to the target block.

  For example, the index is set by the CN information decoding unit 10 when the target block is generated by dividing the upper block (parent block) according to the scan order (processing order) of the target block and the spatial arrangement of the target block. May be. According to the above configuration, by setting the template area of the target block according to the index allocated to the target block, it is possible to set the template area according to the processing order and spatial arrangement of the target block. Play.

  Next, setting of a template area in template matching according to the present example will be described in detail with reference to FIGS. 28 to 30 are diagrams showing an example of a template area set by the matching motion deriving unit 30373 according to this example.

  In FIG. 28 to FIG. 30, a block given T is a target block to be subjected to template matching, and a block given P is the immediately preceding block. In this example, each block is decoded in the order of raster scan. Also, the filled area shown in FIGS. 28 to 30 is the template area of the target block (T).

  First, an index allocated to a block generated by QT division and a template area corresponding to the index will be described. (A) to (d) of FIG. 28 are diagrams showing an example of an index allocated to a block generated by QT division and a template region corresponding to the index.

  FIG. 28A is a diagram illustrating an example of an index allocated to the upper left block generated by the QT division and a template region corresponding to the index. . As shown in (a) of FIG. 28, blk_idx = 0 is allocated as an index by the CN information decoding unit 10 to the upper left block generated by the QT division. For the block to which blk_idx = 0 is assigned, the matching motion derivation unit 30373 does not set the template area using the index.

  FIG. 28B is a diagram illustrating an example of an index allocated to the upper right block generated by the QT division and a template region corresponding to the index. As shown in (b) of FIG. 28, blk_idx = 1 is assigned as an index by the CN information decoding unit 10 to the upper right block generated by the QT division. The block immediately before the upper right block is the upper left block generated by the QT division. In order to avoid that the template area of the upper right block is included in the immediately preceding block (upper left block), an area adjacent to the upper side of the target block is set in the template area of the upper right block. That is, the matching motion derivation unit 30373 sets a region adjacent to the upper side of the target block in the template region of the block to which blk_idx = 1 is allocated.

  FIG. 28C is a diagram illustrating an example of an index allocated to the lower left block generated by the QT division and a template region corresponding to the index. As shown in (c) of FIG. 28, blk_idx = 2 is allocated as an index to the lower left block generated by the QT division. The block immediately before the lower left block is the upper right block generated by the QT division. That is, the area adjacent to the upper side of the lower left block and the area adjacent to the left side are not included in the immediately preceding block (upper right block). Therefore, a region adjacent to the upper side of the target block and a region adjacent to the left side are set in the template region of the lower left block. That is, the matching motion deriving unit 30373 sets a region adjacent to the upper side of the target block and a region adjacent to the left side of the target block in the template region of the block to which blk_idx = 2 is allocated.

  FIG. 28D is a diagram illustrating an example of an index allocated to the lower right block generated by QT division and a template region corresponding to the index. As shown in (d) of FIG. 28, blk_idx = 3 is allocated by the CN information decoding unit 10 as an index to the lower right block generated by the QT division. The block immediately before the lower right block is the lower left block generated by the QT division. In order to avoid that the template area of the lower right block is included in the immediately preceding block (lower left block), an area adjacent to the upper side of the target block is set in the template area of the lower right block. That is, the matching motion derivation unit 30373 sets a region adjacent to the upper side of the target block in the template region of the block to which blk_idx = 3 is allocated.

The template region setting by the matching motion deriving unit 30373 in the block generated by QT division (when split_cu_flag == 1) can be expressed as the following equation.
availAbove = (blk_idx> 0)? 1: 0
availLeft = (blk_idx == 2)? 1: 0
The availAbove is a flag indicating whether or not an area adjacent to the upper side of the target block can be used as a template area. The availLeft is a flag indicating whether or not an area adjacent to the left side of the target block can be used as a template area. When the value indicated by each flag is 0, it indicates that the corresponding area is unusable, and when the value indicated by each flag is 1, it indicates that the corresponding area is available.

  Next, an index allocated to a block generated by BT division and TT division and a template area corresponding to the index will be described. FIGS. 29A and 29B are diagrams showing an example of an index allocated to a block generated by BT division in the vertical direction and a template region corresponding to the index.

  FIG. 29A is a diagram illustrating an example of an index allocated to the left block generated by the BT division in the vertical direction and a template region corresponding to the index. As shown in (a) of FIG. 29, blk_idx = 0 is assigned by the CN information decoding unit 10 as an index to the left block generated by the BT division in the vertical direction. For the block to which blk_idx = 0 is assigned, the matching motion derivation unit 30373 does not set the template area using the index.

  FIG. 29B is a diagram illustrating an example of an index allocated to the right block generated by the BT division in the vertical direction and a template region corresponding to the index. As shown in (b) of FIG. 29, blk_idx = 1 is allocated as an index by the CN information decoding unit 10 to the right block generated by BT division. Also, the block immediately before the right block is the left block generated by the BT division. In order to avoid that the template area of the right block is included in the immediately preceding block (left block), an area adjacent to the upper side of the target block is set in the template area of the right block. That is, the matching motion derivation unit 30373 sets the template area according to the division direction of the BT division and the index assigned to the target block.

  FIGS. 30A to 30C are diagrams showing an example of an index allocated to a block generated by TT division in the horizontal direction and a template region corresponding to the index.

  FIG. 30A is a diagram illustrating an example of an index allocated to the upper block generated by the TT division in the horizontal direction and a template region corresponding to the index. As shown in FIG. 30A, blk_idx = 0 is assigned as an index by the CN information decoding unit 10 to the upper block generated by the TT division in the horizontal direction. For a block to which blk_idx = 0 is assigned, the matching motion derivation unit 30373 does not set a template area using the index.

  FIG. 30B is a diagram illustrating an example of an index allocated to the central block generated by the TT division in the horizontal direction and a template area corresponding to the index. As shown in FIG. 30B, the CN information decoding unit 10 assigns blk_idx = 1 as an index to the central block generated by the TT division in the horizontal direction. Further, the block immediately before the central block is the upper block generated by the TT division. In order to avoid that the template area of the central block is included in the immediately preceding block (upper block), an area adjacent to the left side of the target block is set in the template area of the central block.

  FIG. 30C is a diagram illustrating an example of an index allocated to a lower block generated by the TT division in the horizontal direction and a template region corresponding to the index. As shown in FIG. 30C, blk_idx = 2 is assigned by the CN information decoding unit 10 as an index to the lower block generated by the TT division in the horizontal direction. In addition, the block immediately before the lower block is a central block generated by the TT division. In order to avoid that the template area of the lower block is included in the immediately preceding block (center block), an area adjacent to the left side of the target block is set in the template area of the lower block. That is, the matching motion derivation unit 30373 sets a template region according to the division direction of the TT division and the index assigned to the target block.

The template region setting by the matching motion deriving unit 30373 in the block generated by BT division or TT division (when split_mt_flag == 1) can be expressed as the following equation. Note that split_mt_flag is a flag indicating whether to perform BT partitioning or TT partitioning. When the value of the flag indicates 1, the CN information decoding unit 10 performs BT partitioning or TT partitioning.
availAbove = (mt_dir_flag == 1) &&(blk_idx> 0)? 1: 0
availLeft = (mt_dir_flag == 0) &&(blk_idx> 0)? 1: 0
Note that mt_dir_flag is a division direction flag indicating the division direction of BT division or TT division. When the value of the flag is 1, the division direction is the vertical direction, and when the value of the flag is 0, the division direction Is horizontal.

  In the above example, the template region of the block generated by the vertical BT division and the horizontal TT division has been described. On the other hand, the above-described configuration may be applied as appropriate to a template region of a block generated by horizontal BT division and vertical TT division.

(Example 3 of template area setting in template matching)
The target block according to this example is generated by dividing an upper block (parent block) that is a block higher than the target block. Also, the matching motion deriving unit 30373 sets the template area according to both the index allocated to the target block and the index allocated to the upper block.

  According to the above configuration, the matching motion deriving unit 30373 sets the template area of the target block using the index allocated to the upper block in addition to the index allocated to the target block. Therefore, there is an effect that the template area excluding the area included in the immediately preceding block can be accurately set.

  Next, setting of a template area in template matching according to this example will be described in detail with reference to FIG. FIG. 31 is a diagram showing an example of a template area set by the matching motion deriving unit 30373 according to this example.

  In FIG. 31, blocks marked with T are target blocks that are targets of template matching. The filled area is the template area of the target block (T). FIG. 31 shows template regions of a plurality of blocks. As shown in FIG. 31, the CTU is QT-divided, and each upper block generated by the QT division is BT-divided to generate a block (CU). Specifically, the upper left upper block and the lower left upper block generated by QT dividing the CTU are BT-divided in the vertical direction. Further, the upper right upper block and the lower right upper block generated by QT dividing the CTU are BT divided in the horizontal direction.

  The CN information decoding unit 10 assigns the index parent_blk_idx == 0 to the upper left upper block generated by dividing the CTU by QT. Also, the CN information decoding unit 10 assigns the index blk_idx == 0 to the left block generated by performing BT division on the upper left upper block in the vertical direction, and assigns the index blk_idx == 1 to the right block. blk_idx is a number written in each block in the figure.

  Also, the CN information decoding unit 10 assigns the index parent_blk_idx = 1 to the upper right upper block generated by dividing the CTU by QT. Also, the CN information decoding unit 10 assigns the index blk_idx = 0 to the upper block generated by performing BT division on the upper right upper block in the horizontal direction, and assigns the index blk_idx = 1 to the lower block.

  Also, the CN information decoding unit 10 assigns the index parent_blk_idx = 2 to the upper left lower block generated by dividing the CTU by QT. Also, the CN information decoding unit 10 assigns the index blk_idx = 0 to the left block generated by BT division of the lower left upper block in the vertical direction, and assigns the index blk_idx = 1 to the right block.

  Also, the CN information decoding unit 10 assigns the index parent_blk_idx = 3 to the upper right lower block generated by QT-dividing the CTU. Also, the CN information decoding unit 10 assigns the index blk_idx = 0 to the upper block generated by BT division of the lower right upper block in the horizontal direction, and assigns the index blk_idx = 1 to the lower block.

  FIG. 31A shows an example of a template area of each block to which blk_idx = 0 is assigned.

  As shown in FIG. 31 (a), the matching motion deriving unit 30373 uses the left block template region generated by performing BT division on the upper block to which parent_blk_idx = 0 is allocated in the vertical direction, and the index allocated to the block. Do not set using.

  Also, the matching motion derivation unit 30373 sets a region adjacent to the upper side of the target block in the template region of the upper block generated by performing BT division on the upper block to which parent_blk_idx = 1 is allocated in the horizontal direction.

  Also, the matching motion derivation unit 30373 sets a region adjacent to the left side of the target block in the template region of the left block generated by performing BT division on the upper block to which parent_blk_idx = 2 is allocated in the vertical direction.

  Also, the matching motion derivation unit 30373 sets a region adjacent to the upper side of the target block in the template region of the upper block generated by BT-dividing the upper block to which parent_blk_idx = 3 is allocated in the horizontal direction.

  FIG. 31B is a diagram illustrating an example of a template area set in each block to which blk_idx = 1 is assigned.

  As shown in FIG. 31 (b), the matching motion deriving unit 30373 is adjacent to the upper right side of the target block in the template area of the right block generated by BT-dividing the upper block to which parent_blk_idx = 0 is assigned in the vertical direction. Set the area to be used.

  Also, the matching motion derivation unit 30373 sets a region adjacent to the left side of the target block in the template region of the lower block generated by performing BT division on the upper block to which parent_blk_idx = 1 is allocated in the horizontal direction.

  Also, the matching motion deriving unit 30373 sets an area adjacent to the upper side of the target block in the template area of the right block generated by BT-dividing the upper block to which parent_blk_idx = 2 is assigned in the vertical direction.

  Also, the matching motion derivation unit 30373 sets a region adjacent to the left side of the target block in the template region of the lower block generated by performing BT division on the upper block to which parent_blk_idx = 3 is allocated in the horizontal direction.

Setting of the template area by the matching motion deriving unit 30373 using the index allocated to the target block and the index allocated to the upper block can be expressed as the following expression.
availAbove =
{(mt_dir_flag == 1) &&(blk_idx> 0)} ||
{(parent_blk_idx == 1) && (blk_idx == 0)} ||
{(parent_blk_idx == 3) && (blk_idx == 0)} ||

availLeft =
{(mt_dir_flag == 0) &&(blk_idx> 0)} ||
{(parent_blk_idx == 2) && (blk_idx == 0)}
In the above example, the template area of the target block generated by BT division of the upper block has been described. On the other hand, the above example may be applied as appropriate to the template area of the target block generated by TT-dividing the upper block.

  Further, as described in “Example 2 of template area setting in template matching”, the setting of the template area by the matching motion deriving unit 30373 in the block generated by the QT division can be expressed as an expression.

The setting of the template area of the target block generated by the BT division of this example and the setting of the template area of the target block generated by the QT division shown in “Example 2 of template area setting in template matching” are as follows: Can be shown.
availAbove =
{(split_cu_flag == 1) &&(blk_idx> 0} ||
{(mt_dir_flag == 1) &&(blk_idx> 0)} ||
{(parent_blk_idx == 1) && (blk_idx == 0)} ||
{(parent_blk_idx == 3) && (blk_idx == 0)}

availLeft =
{(split_cu_flag == 1) && (blk_idx == 2)} ||
{(mt_dir_flag == 0) &&(blk_idx> 0)} ||
{(parent_blk_idx == 2) && (blk_idx == 0)}
(Example 4 of template area setting in template matching)
The matching motion deriving unit 30373 according to this example sets only pixels located above the target block as candidates for the template of the target block.

  For example, when the immediately preceding block becomes a block adjacent to the upper side of the target block, this is only when the second and subsequent blocks generated by TT division or BT division in the horizontal direction become the target block. Therefore, in many target blocks, the immediately preceding block is not an adjacent block on the upper side. Therefore, according to said structure, it can suppress that the pixel contained in the block processed immediately before an object block is set to the template area | region of template matching.

  FIGS. 32 to 34 are diagrams showing an example of a template area set by the matching motion deriving unit 30373 according to this example.

  The CTU division shown in FIGS. 32 to 34 is the same as the example shown in “Example 1 of template region setting in template matching” described above. Therefore, detailed description is not given here.

  In FIGS. 32 to 34, a block with T is a target block to be subjected to template matching, and a block with P is the immediately preceding block. Also, the filled area shown in FIGS. 32 to 34 is the template area of the target block (T).

  FIG. 32A shows a template area when the upper left block generated by the first QT division is the target block.

  (B) and (c) of FIG. 32 show template regions when each block generated by further BT-dividing the upper right block generated by the first QT division in the vertical direction becomes the target block. ing.

  (A) to (d) of FIG. 33 show template regions in the case where each block generated by further QT-dividing the lower left block generated by the first QT division becomes the target block.

  (A) to (c) of FIG. 34 show template regions when each block generated by further TT-dividing the lower right block generated by the first QT division in the horizontal direction becomes the target block. Show. In FIGS. 32 to 34, only in the cases shown in FIGS. 34 (b) and 34 (c), the immediately preceding block becomes a block adjacent to the upper side.

  As shown in FIGS. 32 to 34, the matching motion deriving unit 30373 sets a region adjacent to the upper side of the target block as a template region. Also, the matching motion derivation unit 30373 does not set a block adjacent to the left side of the target block as a template region. That is, in this example, the matching motion deriving unit 30373 always sets aboveAvail to 1 and always sets leftAvail to 0.

(Example 5 of template area setting in template matching)
The matching motion derivation unit 30373 according to this example sets a template region according to how the target block is a divided block.

  Specifically, the matching motion deriving unit 30373 sets the template region of the target block according to which direction the BT division, the TT division or the QT division in which direction the target block is generated.

  According to the above configuration, the matching motion deriving unit 30373 sets the template area of the target block according to the BT division and TT division directions for generating the target block. In addition, when the division for generating the target block is the QT division, the matching motion deriving unit 30373 sets a template region corresponding to the division. Therefore, it can suppress that the pixel contained in the block processed immediately before an object block is set to the template area | region of template matching.

  Setting of a template area in template matching according to this example will be described in detail with reference to FIGS. FIGS. 35 to 37 are diagrams showing an example of a template area set by the matching motion deriving unit 30373 according to this example.

  The CTU division shown in FIGS. 35 to 37 is the same as the example shown in “Example 1 of template area setting in template matching” described above. Therefore, detailed description is not given here.

  In FIG. 35 to FIG. 37, a block with T is a target block to be subjected to template matching, and a block with P is the immediately preceding block. Also, the filled area shown in FIGS. 35 to 37 is the template area of the target block (T).

  FIG. 35A shows a template region when the upper left block generated by the first QT division is the target block.

  (B) and (c) of FIG. 35 show a template area when each block generated by further BT-dividing the upper right block generated by the first QT division in the vertical direction becomes the target block. ing.

  36A to 36D show template regions in the case where each block generated by further QT-dividing the lower left block generated by the first QT division becomes the target block.

  (A) to (c) of FIG. 37 show template regions when each block generated by further TT-dividing the lower right block generated by the first QT division in the horizontal direction becomes the target block. Show.

  As shown in FIGS. 35B and 35C, in this example, the matching motion derivation unit 30373 uses the template area of the target block generated by the vertical BT division and the vertical TT division as the target block. Set to the upper adjacent area. In addition, as shown in FIGS. 37A to 37C, in this example, the matching motion deriving unit 30373 targets the template region of the target block generated by the horizontal BT division and the horizontal TT division. Set to the area adjacent to the left side of the block. Further, as shown in FIGS. 36A to 36D, in this example, the matching motion derivation unit 30373 sets the template area of the target block generated by the QT division to an area adjacent to the upper side of the target block. May be.

  That is, for a target block generated by vertical BT partitioning and vertical TT partitioning (split_mt_dir == 1), the matching motion derivation unit 30373 has a template region of the target block adjacent to the upper side of the target block. Set to. For the target block generated by the horizontal BT division and the horizontal TT division (split_mt_dir == 0), the matching motion derivation unit 30373 sets the template area of the target block adjacent to the left side of the target block. Set to.

The setting of the template area according to the target block dividing method by the matching motion deriving unit 30373 can be expressed as the following expression.
aboveAvail = (split_mt_dir == 1)? 1: 0
leftAvail = (split_mt_dir == 0)? 1: 0
Further, the matching motion deriving unit 30373 is adjacent to the template block of the target block generated by the QT division (split_cu_split == 1) above the target block. The above setting can be expressed as the following equation.
aboveAvail = (split_cu_split == 1)? 1: 0
(Example 6 of template area setting in template matching)
In this example, modified examples of “Example 4 of template region setting in template matching” and “Example 5 of template region setting in template matching” will be described with reference to FIG. FIG. 38 is a diagram illustrating an example of a template region set by the matching motion derivation unit 30373 according to the present modification.

  The filled area shown in FIG. 38 is a template area of the target block (CU). As shown in (a) and (c) of FIG. 38, the region adjacent to the upper side of the target block set by the matching motion deriving unit 30373 may be extended from the upper side to the left side of the target block. Further, as shown in FIGS. 38B and 38D, the region adjacent to the left side of the target block set by the matching motion deriving unit 30373 may be extended from the left side to the upper side of the target block.

(Example 7-1 of template area setting in template matching)
The matching motion deriving unit 30373 according to this example sets the target block according to a scan order including at least a part of the processing order that goes back from the downstream side in the raster scan order to the upstream side in the raster scan order. Hereinafter, the scan in the order from the downstream side in the raster scan order to the upstream side in the raster scan order is referred to as a bi-predictive scan.

  Here, the scanning order of the blocks when the divided blocks are scanned by the raster scan and the scanning order of the blocks when the divided blocks are scanned by the bi-predictive scan will be described.

  39A to 39C are diagrams illustrating an example of the scan order when the divided blocks are scanned by the raster scan. As shown in FIG. 39 (a), QT-divided blocks are scanned in the order of upper left, upper right, lower left, and lower right. The matching motion deriving unit 30373 performs processing of the blocks divided in the order. Further, as shown in FIG. 39B, the blocks divided in the BT direction in the horizontal direction are scanned in the order of top and bottom. Although not shown in the figure, the blocks that are BT-divided in the vertical direction are scanned in the order of left and right. Also, as shown in FIG. 39C, the blocks that are TT-divided in the horizontal direction are scanned in the order of top, center, and bottom. Although not shown in the figure, the blocks that are TT-divided in the vertical direction are scanned in the order of left, center, and right. The matching motion deriving unit 30373 performs processing of the blocks divided in the order.

  Further, (d) to (f) of FIG. 39 are diagrams illustrating an example of the scan order when the divided blocks are scanned by bi-predictive scanning. As shown in FIG. 39 (d), QT-divided blocks are scanned in the order of upper right, upper left, lower right, and lower left. The matching motion deriving unit 30373 performs processing of the blocks divided in the order. Further, as shown in FIG. 39 (e), the blocks divided into BT in the horizontal direction are scanned in the order of lower and upper. Although not shown in the figure, the blocks that are BT-divided in the vertical direction are scanned in the order of right, left. Also, as shown in FIG. 39 (f), the blocks that have been TT-divided in the horizontal direction are scanned in the order of center, top, and bottom. Although not shown in the figure, the blocks that are TT-divided in the vertical direction are scanned in the order of center, left, and right. The matching motion derivation unit 30373 performs processing of the divided blocks in the order.

  In this example, the matching motion deriving unit 30373 scans the blocks generated by the division according to the bi-predictive scan order.

  40 to 42 are diagrams showing an example of a template area set for the divided blocks by the matching motion deriving unit 30373 according to this example.

  The division of CTUs shown in FIGS. 40 to 42 is the same as the example shown in “Example 1 of template region setting in template matching” described above. Therefore, detailed description is not given here.

  In FIGS. 40 to 42, the numbers given to the blocks indicate the order in which the blocks are scanned. As shown in FIGS. 40 to 42, the matching motion derivation unit 30373 scans the blocks generated by further division after the first QT division in the order of bi-prediction scanning. A block with T is a target block to be subjected to template matching, and a block with P is the immediately preceding block. Also, the filled area shown in FIGS. 40 to 42 is the template area of the target block (T).

  FIG. 40A shows a template region when the upper left block generated by the first QT division is the target block.

  (B) and (c) of FIG. 40 show template regions when the upper right block generated by the first QT division is further subjected to BT division in the vertical direction and each block generated is the target block. ing.

  41A to 41D show template regions in the case where each block generated by further QT-dividing the lower left block generated by the first QT division becomes the target block.

  (A) to (c) of FIG. 42 show template regions in the case where each block generated by further TT-dividing the lower right block generated by the first QT division in the horizontal direction becomes the target block. Show.

  According to said structure, it can suppress that the block adjacent to the left side of an object block and the block adjacent to the upper side of an object block become a block processed immediately before an object block. That is, the image decoding device 31 can start the predicted image generation process for the next block without waiting for the decoding process for the immediately preceding block.

  For the block with scan number 2 shown in FIG. 40 (c) and the block with scan number 9 shown in FIG. 42, etc., the template of the block is the area adjacent to the upper side and the left side. If it is not included in the previous block. For example, when processing is performed in the order of the raster scan described above, the area adjacent to the left side of the block assigned scan number 2 is included in the immediately preceding block and is adjacent to the upper side of the block assigned scan number 9. The area is included in the immediately preceding block. Therefore, the area adjacent to the upper side of the block and the area adjacent to the left side of the block cannot be the template area of the block.

(Example 7-2 of template area setting in template matching)
The matching motion derivation unit (scan order setting unit) 30373 according to this example sets the block scan order in the predicted image generation unit 308 with reference to the flag included in the encoded data.

  According to the above configuration, the matching motion deriving unit 30373 sets the block scan order in the inter predicted image generation unit 309 with reference to the flag included in the encoded data. For example, the order indicated by the flag may be a processing order that goes back from the downstream side in the raster scan order to the upstream side in the raster scan order. In this case, it is possible to suppress the block adjacent to the left side of the target block and the block adjacent to the upper side of the target block from being processed immediately before the target block. That is, the predicted image generation process for the next block can be started without waiting for the decoding process for the immediately preceding block.

  For example, the inter prediction parameter encoding unit 112 of the image encoding device 11 derives alt_cu_scan_flag indicating the scan order of blocks in predictive image generation. When alt_cu_scan_flag == 0, the matching motion deriving unit 30373 derives a motion vector (motion information) of each block divided in the order of raster scan (Z scan). When alt_cu_scan_flag == 1, the matching motion deriving unit 30373 derives (scans) the motion vector of each block divided in the bi-predictive scan order. The matching motion deriving unit 30373 may be configured to derive a motion vector in template matching only when alt_cu_scan_flag == 1, that is, when bi-predictive scanning is indicated.

  The above scan order setting may be expressed by the syntax shown in FIGS. 43 to 45. FIG. 43 is a diagram illustrating an example of syntax for changing the scan order in accordance with alt_cu_scan_flag for the QT-divided block illustrated in FIG. 23. FIG. 44 is a diagram illustrating an example of syntax for changing the scan order according to alt_cu_scan_flag for the TT-divided block illustrated in FIG. 24B. FIG. 45 is a diagram illustrating an example of syntax for changing the scan order in accordance with alt_cu_scan_flag for the BT-divided block illustrated in FIG. 24C.

(Configuration of Image Encoding Device 11)
The matching motion deriving unit 11253 of the image encoding device 11 according to this embodiment may have the same configuration so as to correspond to the above-described matching motion deriving unit 30373 in the image decoding device 31 according to this embodiment.

[Application example]
The image encoding device 11 and the image decoding device 31 described above can be used by being mounted on various devices that perform transmission, reception, recording, and reproduction of moving images. The moving image may be a natural moving image captured by a camera or the like, or an artificial moving image (including CG and GUI) generated by a computer or the like.

  First, it will be described with reference to FIG. 46 that the image encoding device 11 and the image decoding device 31 described above can be used for transmission and reception of moving images.

  FIG. 46A is a block diagram illustrating a configuration of a transmission device PROD_A in which the image encoding device 11 is mounted. As illustrated in (a) of FIG. 46, the transmission apparatus PROD_A modulates a carrier wave with an encoding unit PROD_A1 that obtains encoded data by encoding a moving image, and with the encoded data obtained by the encoding unit PROD_A1. Thus, a modulation unit PROD_A2 that obtains a modulation signal and a transmission unit PROD_A3 that transmits the modulation signal obtained by the modulation unit PROD_A2 are provided. The above-described image encoding device 11 is used as the encoding unit PROD_A1.

  Transmission device PROD_A, as a source of moving images to be input to the encoding unit PROD_A1, a camera PROD_A4 that captures moving images, a recording medium PROD_A5 that records moving images, an input terminal PROD_A6 for inputting moving images from the outside, and An image processing unit A7 that generates or processes an image may be further provided. FIG. 46A illustrates a configuration in which the transmission apparatus PROD_A includes all of these, but some of them may be omitted.

  Note that the recording medium PROD_A5 may be a recording of a non-encoded moving image, or a recording of a moving image encoded by a recording encoding scheme different from the transmission encoding scheme. It may be a thing. In the latter case, a decoding unit (not shown) for decoding the encoded data read from the recording medium PROD_A5 in accordance with the recording encoding method may be interposed between the recording medium PROD_A5 and the encoding unit PROD_A1.

  FIG. 46B is a block diagram illustrating a configuration of a receiving device PROD_B in which the image decoding device 31 is mounted. As illustrated in (b) of FIG. 46, the reception device PROD_B includes a reception unit PROD_B1 that receives a modulation signal, a demodulation unit PROD_B2 that obtains encoded data by demodulating the modulation signal received by the reception unit PROD_B1, and a demodulation A decoding unit PROD_B3 that obtains a moving image by decoding the encoded data obtained by the unit PROD_B2. The above-described image decoding device 31 is used as the decoding unit PROD_B3.

  The receiving device PROD_B is a display destination PROD_B4 for displaying a moving image, a recording medium PROD_B5 for recording a 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 PROD_B6 may be further provided. In FIG. 46B, a configuration in which all of these are provided in the receiving device PROD_B is illustrated, but a part may be omitted.

  Note that the recording medium PROD_B5 may be used for recording a non-encoded moving image, or is encoded using a recording encoding method different from the transmission encoding method. May be. In the latter case, an encoding unit (not shown) for encoding the moving image acquired from the decoding unit PROD_B3 according to the recording encoding method may be interposed between the decoding unit PROD_B3 and the recording medium PROD_B5.

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

  For example, a terrestrial digital broadcast broadcasting station (such as broadcasting equipment) / receiving station (such as a television receiver) is an example of a transmitting device PROD_A / receiving device PROD_B that transmits and receives a modulated signal by wireless broadcasting. A broadcasting station (such as broadcasting equipment) / receiving station (such as a television receiver) of cable television broadcasting is an example of a transmitting device PROD_A / receiving device PROD_B that transmits and receives a modulated signal by cable broadcasting.

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

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

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

  FIG. 47A is a block diagram illustrating a configuration of a recording apparatus PROD_C in which the above-described image encoding device 11 is mounted. As shown in (a) of FIG. 47, the recording apparatus PROD_C includes an encoding unit PROD_C1 that obtains encoded data by encoding a moving image, and the encoded data obtained by the encoding unit PROD_C1 on the recording medium PROD_M. A writing unit PROD_C2 for writing. The above-described image encoding device 11 is used as the encoding unit PROD_C1.

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

  In addition, the recording device PROD_C is a camera PROD_C3 that captures moving images as a source of moving images to be input to the encoding unit PROD_C1, an input terminal PROD_C4 for inputting moving images from the outside, and a reception for receiving moving images A unit PROD_C5 and an image processing unit PROD_C6 for generating or processing an image may be further provided. FIG. 47A illustrates a configuration in which the recording apparatus PROD_C includes all of these, but some of them may be omitted.

  The receiving unit PROD_C5 may receive a non-encoded moving image, or may receive encoded data encoded by a transmission encoding scheme different from the recording encoding scheme. You may do. In the latter case, a transmission decoding unit (not shown) that decodes encoded data encoded by the transmission encoding method may be interposed 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, and the like (in this case, the input terminal PROD_C4 or the receiving unit PROD_C5 is a main source of moving images). . In addition, a camcorder (in this case, the camera PROD_C3 is a main source of moving images), a personal computer (in this case, the receiving unit PROD_C5 or the image processing unit C6 is a main source of moving images), a smartphone (this In this case, the camera PROD_C3 or the reception unit PROD_C5 is a main source of moving images), and the like is also an example of such a recording apparatus PROD_C.

  FIG. 47 (b) is a block diagram showing a configuration of a playback device PROD_D in which the above-described image decoding device 31 is mounted. As shown in (b) of FIG. 47, the playback device PROD_D reads a moving image by decoding a read unit PROD_D1 that reads encoded data written on the recording medium PROD_M and a read unit PROD_D1 that reads the encoded data. And a decoding unit PROD_D2 to obtain. The above-described image decoding device 31 is used as the decoding unit PROD_D2.

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

  In addition, the playback device PROD_D has a display unit 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. PROD_D5 may be further provided. FIG. 47B illustrates a configuration in which the playback apparatus PROD_D includes all of these, but some of them may be omitted.

  The transmission unit PROD_D5 may transmit a non-encoded moving image, or transmits encoded data encoded by a transmission encoding scheme different from the recording encoding scheme. You may do. In the latter case, it is preferable to interpose an encoding unit (not shown) that encodes a moving image using a transmission encoding method between the decoding unit PROD_D2 and the transmission unit PROD_D5.

  Examples of such a playback device PROD_D include a DVD player, a BD player, and an HDD player (in this case, an output terminal PROD_D4 to which a television receiver or the like is connected is a main moving image supply destination). . In addition, a television receiver (in this case, the display PROD_D3 is a main supply destination of moving images), a digital signage (also referred to as an electronic signboard or an electronic bulletin board), and the display PROD_D3 or the transmission unit PROD_D5 is the main supply of moving images Desktop PC (in this case, output terminal PROD_D4 or transmission unit PROD_D5 is the main video source), laptop or tablet PC (in this case, display PROD_D3 or transmission unit PROD_D5 is video) A smartphone (which is a main image supply destination), a smartphone (in this case, the display PROD_D3 or the transmission unit PROD_D5 is a main moving image supply destination), and the like are also examples of such a playback device PROD_D.

(Hardware implementation and software implementation)
Each block of the image decoding device 31 and the image encoding device 11 described above may be realized in hardware by a logic circuit formed on an integrated circuit (IC chip), or may be a CPU (Central Processing Unit). You may implement | achieve by software using.

  In the latter case, each device includes a CPU that executes instructions of a program that realizes each function, a ROM (Read Only Memory) that stores the program, a RAM (Random Access Memory) that expands the program, the program, and various types A storage device (recording medium) such as a memory for storing data is provided. The object of the embodiment of the present invention is a record in which the program code (execution format program, intermediate code program, source program) of the control program for each of the above devices, which is software that realizes the above-described functions, is recorded in a computer-readable manner This can also be achieved by supplying a medium to each of the above devices, and reading and executing the program code recorded on the recording medium by the computer (or CPU or MPU).

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

  Further, each of the above devices may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited as long as it can transmit the program code. 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) Network), telephone line network, mobile communication network, satellite communication network, and the like. The transmission medium constituting the communication network may be any medium that can transmit the program code, and is not limited to a specific configuration or type. For example, infra-red data such as IrDA (Infrared Data Association) or remote control, 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, etc. , BlueTooth (registered trademark), IEEE802.11 wireless, HDR (High Data Rate), NFC (Near Field Communication), DLNA (Digital Living Network Alliance: registered trademark), mobile phone network, satellite line, terrestrial digital broadcasting network, etc. It can also be used wirelessly. The embodiment of the present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  The 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, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.

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

11... Image coding apparatus 101... Prediction image generation unit 112... Inter prediction parameter coding unit (scan order setting unit)
11253 ... Matching motion deriving unit (motion information deriving unit, scan order setting unit)
31... Image decoding device 309... Inter prediction image generation unit (prediction image generation unit)
30373 ... Matching motion deriving unit (motion information deriving unit, scan order setting unit)

Claims (16)

An image decoding device for decoding encoded data,
A prediction image generation unit that generates a prediction image of the target block;
The predicted image generation unit
Of the blocks not adjacent to the target block,
A prediction image of the target block is generated with reference to motion information of a block in which at least one of a vertical distance and a horizontal distance from the boundary of the coding tree unit including the target block is equal to or less than a predetermined value An image decoding apparatus characterized by: An image decoding device for decoding encoded data,
A motion information deriving unit for deriving motion information of the target block, and a predicted image generating unit for generating a predicted image of the target block with reference to the motion information,
The motion information deriving unit
By performing template matching with reference to the decoded template area set according to the target block, the motion information of the target block is derived,
The image decoding apparatus, wherein the motion information deriving unit does not set a pixel included in a block processed immediately before the target block in the template region. An image decoding device for decoding encoded data,
A motion information deriving unit for deriving motion information of the target block, and a predicted image generating unit for generating a predicted image of the target block with reference to the motion information,
The motion information deriving unit
By performing template matching with reference to the decoded template area set according to the target block, the motion information of the target block is derived,
An index is allocated to the target block,
The image decoding apparatus, wherein the motion information deriving unit sets the template region in accordance with an index assigned to the target block. The target block is generated by dividing an upper block that is a higher block than the target block,
The said motion information derivation | leading-out part sets the said template area | region according to the index of both the index allocated to the said object block, and the index allocated to the said high-order block, The Claim 3 characterized by the above-mentioned. The image decoding device described. An image decoding device for decoding encoded data,
A motion information deriving unit for deriving motion information of the target block, and a predicted image generating unit for generating a predicted image of the target block with reference to the motion information,
The motion information deriving unit
By performing template matching with reference to the decoded template area set according to the target block, the motion information of the target block is derived,
The image decoding apparatus according to claim 1, wherein the motion information deriving unit sets only pixels located above the target block as candidates for the template region. An image decoding device for decoding encoded data,
A motion information deriving unit for deriving motion information of the target block, and a predicted image generating unit for generating a predicted image of the target block with reference to the motion information,
The motion information deriving unit
By performing template matching with reference to the decoded template area set according to the target block, the motion information of the target block is derived,
The image decoding apparatus according to claim 1, wherein the motion information deriving unit sets the template area according to how the target block is a divided block. An image decoding device for decoding encoded data,
A motion information deriving unit for deriving motion information of the target block and a predicted image generating unit for generating a predicted image of the target block with reference to the motion information;
The motion information deriving unit
By performing template matching with reference to the decoded template area set according to the target block, the motion information of the target block is derived,
An image decoding apparatus, wherein a target block is set according to a scan order including at least a part of a processing order that goes back from the downstream side in the raster scan order to the upstream side in the raster scan order. An image decoding device for decoding encoded data,
A motion information deriving unit for deriving motion information of the target block;
A predicted image generation unit that generates a predicted image of the target block with reference to the motion information;
A scan order setting unit that sets the scan order of blocks in the predicted image generation unit,
The motion information deriving unit
By performing template matching with reference to the decoded template area set according to the target block, the motion information of the target block is derived,
The image decoding apparatus, wherein the scan order setting unit sets a scan order of blocks in the predicted image generation unit with reference to a flag included in the encoded data. An image encoding device that encodes a residual between a predicted image and an encoding target image,
A prediction image generation unit that generates a prediction image of the target block;
The predicted image generation unit
Of the blocks not adjacent to the target block,
A prediction image of the target block is generated with reference to motion information of a block in which at least one of a vertical distance and a horizontal distance from the boundary of the coding tree unit including the target block is equal to or less than a predetermined value An image encoding apparatus characterized by: An image encoding device that encodes a residual between a predicted image and an encoding target image,
A motion information deriving unit for deriving motion information of the target block, and a predicted image generating unit for generating a predicted image of the target block with reference to the motion information,
The motion information deriving unit
By performing template matching with reference to the encoded template area set according to the target block, the motion information of the target block is derived,
The image coding apparatus according to claim 1, wherein the motion information deriving unit does not set a pixel included in a block processed immediately before the target block in the template region. An image encoding device that encodes a residual between a predicted image and an encoding target image,
A motion information deriving unit for deriving motion information of the target block, and a predicted image generating unit for generating a predicted image of the target block with reference to the motion information,
The motion information deriving unit
By performing template matching with reference to the encoded template area set according to the target block, the motion information of the target block is derived,
An index is allocated to the target block,
The image coding apparatus, wherein the motion information deriving unit sets the template region in accordance with an index assigned to the target block. The target block is generated by dividing an upper block that is a higher block than the target block,
The motion information deriving unit sets the template region according to both the index allocated to the target block and the index allocated to the upper block. The image encoding device described. An image encoding device that encodes a residual between a predicted image and an encoding target image,
A motion information deriving unit for deriving motion information of the target block, and a predicted image generating unit for generating a predicted image of the target block with reference to the motion information,
The motion information deriving unit
By performing template matching with reference to the encoded template area set according to the target block, the motion information of the target block is derived,
The image coding apparatus according to claim 1, wherein the motion information deriving unit sets only pixels located above the target block as candidates for the template region. An image encoding device that encodes a residual between a predicted image and an encoding target image,
A motion information deriving unit for deriving motion information of the target block, and a predicted image generating unit for generating a predicted image of the target block with reference to the motion information,
The motion information deriving unit
By performing template matching with reference to the decoded template area set according to the target block, the motion information of the target block is derived,
The image coding apparatus according to claim 1, wherein the motion information deriving unit sets the template area according to how the target block is a divided block. An image encoding device that encodes a residual between a predicted image and an encoding target image,
A motion information deriving unit for deriving motion information of the target block and a predicted image generating unit for generating a predicted image of the target block with reference to the motion information;
The motion information deriving unit
By performing template matching with reference to the decoded template area set according to the target block, the motion information of the target block is derived,
An image encoding device, wherein a target block is set according to a scan order including at least a part of a processing order that goes back from a downstream side in a raster scan order to an upstream side in a raster scan order. An image encoding device that encodes a residual between a predicted image and an encoding target image,
A motion information deriving unit for deriving motion information of the target block;
A predicted image generation unit that generates a predicted image of the target block with reference to the motion information;
A scan order setting unit for setting the scan order of blocks in the predicted image generation unit,
The motion information deriving unit
By performing template matching with reference to the encoded template area set according to the target block, the motion information of the target block is derived,
The image coding apparatus, wherein the scan order setting unit includes a flag indicating a scan order of blocks in the predicted image generation unit in data to be encoded.

Images