JP2016072941A - Dmm prediction device, image decoding device and image encoding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that, when deriving a DC prediction value in each of regions of an object block in DMM prediction, since the DC prediction value is derived by selecting a reference pixel to be utilized for each of the regions on the basis of a vertical edge flag and a horizontal edge flag which are derived from a wedgelet pattern and a pixel differential between the reference pixels, there are many conditional branches and processing is complicated.SOLUTION: In DC prediction value derivation processing in each region Ri (i=0, 1) of the object block in the DMM prediction, the reference pixel corresponding to the vertical edge flag and the horizontal edge flag derived from the wedgelet pattern is selected without calculating a pixel strength between the reference pixels, and the DC prediction value in each region Ri (i=0, 1) is derived.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image decoding apparatus that decodes encoded data representing an image, and an image encoding apparatus that generates encoded data by encoding an image.

  The multi-view image encoding technique includes a parallax predictive encoding that reduces the amount of information by predicting a parallax between images when encoding images of a plurality of viewpoints, and a decoding method corresponding to the encoding method. Has been proposed. A vector representing the parallax between viewpoint images is called a displacement vector. The displacement vector is a two-dimensional vector having a horizontal element (x component) and a vertical element (y component), and is calculated for each block which is an area obtained by dividing one image. In order to acquire images from a plurality of viewpoints, it is common to use cameras arranged at the respective viewpoints. In multi-viewpoint encoding, each viewpoint image is encoded as a different layer in each of a plurality of layers. A method for encoding a moving image composed of a plurality of layers is generally referred to as scalable encoding or hierarchical encoding. In scalable coding, high coding efficiency is realized by performing prediction between layers. A reference layer without performing prediction between layers is called a base layer, and other layers are called enhancement layers. Scalable encoding in the case where a layer is composed of viewpoint images is referred to as view scalable encoding. At this time, the base layer is also called a base view, and the enhancement layer is also called a non-base view. Furthermore, in addition to view scalable, scalable coding in the case of a texture layer (image layer) composed of texture (image) and a depth layer (distance image layer) composed of depth map (distance image) is a three-dimensional scalable code. It is called “Kake”.

  For example, there is a HEVC-based three-dimensional scalable coding technique of Non-Patent Document 1. In Non-Patent Document 1, there is a depth encoding tool called DMM prediction (also called depth intra prediction) in order to efficiently encode a depth map.

  DMM prediction basically uses a depth model in which a target block (also referred to as a depth block) on a depth map is composed of two non-rectangular flat regions, and the depth value of each flat region is expressed by a fixed value. Is based. The depth model is composed of partition information (also referred to as a wedgelet pattern) representing an area to which each pixel belongs, and depth value information (also referred to as DC offset information) of each area. Also, the depth prediction value (DC prediction value) of each region is predicted from decoded pixels (reference pixels) adjacent to the target block.

`` 3D-HEVC Draft Text 5 (JCT3V-I1001v3) '', Joint Collaborative Team on 3D Video Coding Extension Development of ITU-T SG16 WP3 and ISO / IEC JTC1 / SC29 / WG11 9th Meeting: Sapporo, JP, 3-9 July, 2014 (released on August 13, 2014)

  However, in the conventional technology, when the DC prediction value of each area of the target block is derived, the vertical edge flag vertEdgeFlag, the horizontal edge flag horEdgeFlag, and the pixel difference (pixel intensity) between the reference pixels derived from the wedgelet pattern horAbsDiff Based on vertAbsDiff, as shown in FIGS. 20A to 20E, the division pattern of the target block is divided into the following five cases, and each region Ri (i = 0,1 ) To select a reference pixel to be used, and to derive a DC prediction value.

(a) (vertEdgeFlag, horEdgeFlag) == (0,0) &&horAbsDiff> vertAbsDiff,
(b) (vertEdgeFlag, horEdgeFlag) == (0,0) && horAbsDiff <= vertAbsDiff,
(c) (vertEdgeFlag, horEdgeFlag) == (1,1),
(d) (vertEdgeFlag, horEdgeFlag) == (0,1),
(e) (vertEdgeFlag, horEdgeFlag) == (1,0),
Where horAbsDiff = Abs (p [0] [-1]-p [nS-1] [-1]), vertAbsDiff = Abs (p [-1] [0]-p [-1] [nS-1 ]). In particular, it is necessary to derive the horizontal pixel difference horAbsDiff and the vertical pixel difference vertAbsDiff from the reference pixel in order to further classify the case where both the horizontal edge flag and the vertical flag are 0. There was a problem that is complicated.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a pixel between reference pixels in the DC prediction value derivation process of each region Ri (i = 0,1) of the target block in DMM prediction. Without calculating the intensity, select the reference pixel according to the vertical edge flag and horizontal edge flag derived from the wedgelet pattern, and derive the DC prediction value of each region Ri (i = 0, 1) An object of the present invention is to realize an image decoding device or the like that can reduce the processing amount related to predictive image generation while maintaining encoding efficiency.

  In order to solve the above problem, the DMM prediction unit according to aspect 1 of the present invention provides a wedgelet pattern deriving unit that derives a wedgelet pattern indicating that the target PU is divided into the first region and the second region. Edge flag deriving means for deriving a vertical edge flag and a horizontal edge flag from the wedgelet pattern, DC predicted value deriving means for deriving a DC predicted value of each region from reference pixels of the target PU, and the wedgelet pattern , A DMM prediction device comprising a predicted image derivation unit for deriving a predicted image of the target PU based on the DC predicted value of each region and the DC offset information of each region, wherein the DC predicted value derivation unit includes: When the vertical edge flag is equal to the horizontal edge flag, when the vertical edge flag is 0 and the horizontal edge flag is 1, When the edge flag is 1 and the horizontal edge flag is 0, the reference pixels used for deriving the DC predicted value of each region are different from each other.

  In order to solve the above problem, in the DMM prediction apparatus according to aspect 2 of the present invention, in the aspect 1, the DC prediction value deriving means further includes the case where the vertical edge flag and the horizontal edge flag are equal, Based on the upper left pixel of the target PU, an average value of a reference pixel at a position of −1 in the x direction and a position of 0 in the y direction and a reference pixel at a position of 0 in the x direction and −1 in the y direction , A DC prediction value for the first region, and a reference pixel at a position of 2 * nS-1 in the x direction and 2 * nS-1 in the x direction and 2 * in the x direction with respect to the upper left pixel of the target PU. An average value of the reference pixel at a position of −1 in the nS−1 and y direction is derived as a DC predicted value for the second region.

  In order to solve the above-described problem, in the DMM prediction apparatus according to aspect 3 of the present invention, in the aspect 1, the DC prediction value deriving unit further includes the vertical edge flag being 0 and the horizontal edge flag being 1. In this case, the reference pixel adjacent to the center pixel on the upper side of the target PU is set as a DC prediction value for the first region, and the reference pixel adjacent to the lower left of the lower leftmost pixel of the target PU is set to DC for the second region. It is derived as a predicted value.

  In order to solve the above-described problem, in the DMM prediction apparatus according to aspect 4 of the present invention, in the aspect 1, the DC prediction value deriving unit further includes the vertical edge flag being 1 and the horizontal edge flag being 0. In this case, the reference pixel adjacent to the left of the central pixel on the left side of the target PU is set as the DC prediction value for the first region, and the reference pixel adjacent to the upper right of the upper right pixel of the target PU is set to DC for the second region. It is derived as a predicted value.

  In order to solve the above-described problem, the DMM prediction apparatus according to aspect 5 of the present invention is the aspect 1 to aspect 4, in which the first region further includes: an uppermost left pixel of the target PU; The region is composed of pixels having a wedgelet pattern value equal to the value of the pixel wedgelet pattern.

  In order to solve the above problem, in the DMM prediction apparatus according to aspect 6 of the present invention, in the aspect 5, the second region is different from the value of the wedgelet pattern of the upper left pixel of the target PU. It is an area composed of pixels having a value of a wedgelet pattern.

  In order to solve the above-described problem, in the DMM prediction apparatus according to aspect 7 of the present invention, in the aspect 6, the edge flag deriving unit further includes a wedge pattern value of the upper left pixel of the target PU and the target When the value of the wedgelet pattern of the upper rightmost pixel of the PU is different, 1 is set as the vertical edge flag, and the value of the wedge pattern of the uppermost right pixel is equal to the value of the wedgelet pattern of the uppermost right pixel. Is characterized in that 0 is set in the vertical edge flag.

  In order to solve the above-described problem, in the DMM prediction apparatus according to aspect 8 of the present invention, in the aspect 7, the edge flag deriving unit further includes a wedge pattern value of the upper left pixel of the target PU and the target When the value of the wedgelet pattern of the lower leftmost pixel of the PU is different, 1 is set in the horizontal flag, and when the value of the wedge pattern of the uppermost left pixel is equal to the value of the wedgelet pattern of the uppermost right pixel , 0 is set as the horizontal edge flag.

  In order to solve the above problem, an image decoding apparatus according to aspect 9 of the present invention decodes the DMM prediction apparatus according to any one of aspects 1 to 8, and DMM prediction mode information related to DMM prediction. An image decoding apparatus including DMM prediction mode information decoding means, wherein the DMM prediction apparatus performs DMM prediction when the DMM prediction mode information indicates DMM prediction.

  In order to solve the above problem, an image coding apparatus according to aspect 10 of the present invention encodes the DMM prediction apparatus according to any one of aspects 1 to 8, and DMM prediction mode information related to DMM prediction. The DMM prediction mode information encoding means includes an encoding means for encoding DMM prediction mode, wherein the DMM prediction apparatus performs DMM prediction when the DMM prediction mode information indicates DMM prediction.

  According to an aspect of the present invention, in DMM prediction, a reference pixel is selected based on a vertical edge flag and a horizontal edge flag derived from a wedgelet pattern related to a target PU, and each region Ri (i = 0, 1 Deriving the DC prediction value of) has the effect of reducing the amount of processing for predictive image generation while maintaining the encoding efficiency.

It is a block diagram which shows the detailed structure of the DC estimated image derivation | leading-out part which concerns on a present Example. 1 is a schematic diagram illustrating a configuration of an image transmission system according to an embodiment of the present invention. It is the functional block diagram shown about the schematic structure of the moving image decoding apparatus which concerns on a present Example. It is a figure which shows the data structure of the encoding data produced | generated by the moving image encoder which concerns on one Embodiment of this invention, and is decoded by the said moving image decoder, Comprising: (a) is a sequence which predetermines sequence SEQ (B) is a picture layer that defines a picture PICT, (c) is a slice layer that defines a slice S, (d) is a tree block layer that defines a tree block included in slice data, (e) These are figures which show the CU layer (coding unit layer) which prescribes | regulates the coding unit (Coding Unit; CU) contained in a coding tree. It is a figure which shows the example of the syntax contained in a CU layer. (A) shows an example of a syntax table related to an intra CU, and (b) is an example of a syntax table related to intra prediction mode extension. It is an example of the syntax which concerns on the DC offset information contained in a CU layer. It is a figure which shows the example of the prediction mode number corresponding to the classification | category of the intra prediction method utilized with the said moving image decoding apparatus. It is a figure which shows the prediction direction corresponding to the identifier of a prediction mode about 33 types of prediction modes which belong to direction prediction. It is a functional block diagram shown about the structural example of the estimated image generation part with which the said moving image decoding apparatus is provided. It is a flowchart which shows the outline of the prediction image generation process of the CU unit in the said prediction image generation part. It is a block diagram which shows the detailed structure of the DMM prediction part which concerns on a present Example. It is a figure for demonstrating the example of the division | segmentation pattern which the state of the vertical edge flag vertEdgeFlag and the horizontal edge flag horEdgeFlag shows. (A) shows an example of the division pattern indicated by (vertEdgeFlag, horEdgeFlag) = (0,0), (b) shows an example of the division pattern indicated by (vertEdgeFlag, horEdgeFlag) = (1,0), c) shows an example of the division pattern indicated by (vertEdgeFlag, horEdgeFlag) = (1,0). It is a figure for demonstrating the reference pixel utilized at the time of DC prediction value derivation | leading-out for every area | region which concerns on a present Example. (A) shows reference pixels used when (vertEdgeFlag, horEdgeFlag) = (0, 0) or (vertEdgeFlag, horEdgeFlag) = (1, 1), and (b) shows (vertEdgeFlag, horEdgeFlag) = (0 , 1) shows the reference pixels used, and (c) is an example of the reference pixels used when (vertEdgeFlag, horEdgeFlag) = (1,0). It is a figure explaining the outline of DMM prediction. (A) is an example showing an edge boundary of an object on a block, and (b) is a division pattern (wedgePattern) indicating that the block is divided into two regions (R0, R1) along the edge boundary of the object. (C) is an example in which a predicted value is assigned to each of the divided areas. It is a figure explaining the production | generation method of the wedgelet pattern based on wedgelet division | segmentation (DMM1) in DMM prediction. (A) is an example of the start point S and the end point E on the block, (b) shows an example of a line segment connecting the start point S and the end point E, and (c) the moving image on the lower right side of the line segment. It is a functional block diagram shown about the structural example of the variable length decoding part with which an image decoding apparatus is provided. It is a figure for demonstrating an example of the wedgelet pattern according to wedge direction wedgeOri (wedgeOri = 0..5) produced | generated in a wedgelet pattern list production | generation part in DMM1 prediction. (A) shows an example of a wedgelet pattern with wedgeOri = 0, (b) shows an example of a wedgelet pattern with wedgeOri = 1, and (c) shows an example of a wedgelet pattern with wedgeOri = 2. (D) shows an example of a wedgelet pattern with wedgeOri = 3, (e) shows an example of a wedgelet pattern with wedgeOri = 4, and (f) shows an example of a wedgelet pattern with wedgeOri = 5. is there. It is a functional block diagram shown about the structure of the moving image encoder which concerns on one Embodiment of this invention. It is the figure shown about the structure of the transmitter which mounts the said moving image encoder, and the receiver which mounts the said moving image decoder. (A) shows a transmitting apparatus equipped with a moving picture coding apparatus, and (b) shows a receiving apparatus equipped with a moving picture decoding apparatus. It is the figure shown about the structure of the recording device which mounts the said moving image encoder, and the reproducing | regenerating apparatus which mounts the said moving image decoder. (A) shows a recording apparatus equipped with a moving picture coding apparatus, and (b) shows a reproduction apparatus equipped with a moving picture decoding apparatus. It is a figure for demonstrating the reference pixel utilized at the time of DC prediction value deriving for every area | region which concerns on a prior art. (A) shows reference pixels used when (vertEdgeFlag, horEdgeFlag) = (0, 0) and horAbsDiff> vertAbsDiff, (b) shows (vertEdgeFlag, horEdgeFlag) = (0, 0), and horAbsDiff ≦ Indicates the reference pixel used when vertAbsDiff, (c) indicates the reference pixel used when (vertEdgeFlag, horEdgeFlag) = (1,1), and (d) shows the reference pixel used when (vertEdgeFlag, horEdgeFlag) = (0,1) (E) shows the reference pixel used when (vertEdgeFlag, horEdgeFlag) = (1,0).

〔Overview〕
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 2 is a schematic diagram showing the configuration of the image transmission system 5 according to the present embodiment.

  The image transmission system 5 is a system that transmits a code obtained by encoding a plurality of layer images and displays an image obtained by decoding the transmitted code. The image transmission system 5 includes an image encoding device 2, a network 3, an image decoding device 2, and an image display device 4.

  The image encoding device 2 receives a signal T indicating a plurality of layer images (also referred to as texture images). A layer image is an image that is viewed or photographed at a certain resolution and a certain viewpoint. When performing view scalable coding in which a three-dimensional image is coded using a plurality of layer images, each of the plurality of layer images is referred to as a viewpoint image. Here, the viewpoint corresponds to the position or observation point of the photographing apparatus. For example, the plurality of viewpoint images are images taken by the left and right photographing devices toward the subject. The image encoding device 2 encodes each of these signals to generate encoded data # 1. Details of the encoded data # 1 will be described later. A viewpoint image is a two-dimensional image (planar image) observed at a certain viewpoint. The viewpoint image is indicated by, for example, a luminance value or a color signal value for each pixel arranged in a two-dimensional plane.

  Hereinafter, one viewpoint image or a signal indicating the viewpoint image is referred to as a picture. In the present embodiment, encoding and decoding of an image including at least a base layer image and an image other than the base layer image (enhancement layer image) is handled as the plurality of layer images. Of the multiple layers, for two layers that have a reference relationship (dependency relationship) in the image or encoding parameter, the image on the reference side is referred to as a first layer image, and the image on the reference side is referred to as a second layer image. . For example, when there is an enhancement layer image (other than the base layer) that is encoded with reference to the base layer, the base layer image is treated as a first layer image and the enhancement layer image is treated as a second layer image. Note that examples of the enhancement layer image include an image of a viewpoint other than the base view and a depth image.

  The viewpoint image is indicated by, for example, a luminance value or a color signal value for each pixel arranged in a two-dimensional plane. Also, the depth map (also called depth map, “depth image”, “depth image”, “distance image”) corresponds to the distance from the viewpoint (photographing device, etc.) of the subject or background included in the subject space. Signal values (referred to as “depth value”, “depth value”, “depth”, etc.), and are image signals composed of signal values (pixel values) for each pixel arranged on a two-dimensional plane. The pixels constituting the depth map correspond to the pixels constituting the viewpoint image. Therefore, the depth map is a clue for representing the three-dimensional object space by using the viewpoint image which is a reference image signal obtained by projecting the object space onto the two-dimensional plane.

  The network 3 transmits the encoded data # 1 generated by the image encoding device 2 to the image decoding device 1. The network 3 is the Internet, a wide area network (WAN), a small network (LAN), or a combination thereof. The network 3 is not necessarily limited to a bidirectional communication network, and may be a unidirectional or bidirectional communication network that transmits broadcast waves such as terrestrial digital broadcasting and satellite broadcasting. The network 3 may be replaced with a storage medium that records encoded data # 1 such as a DVD (Digital Versatile Disc) or a BD (Blu-ray Disc (registered trademark)).

  The image decoding device 1 decodes each of the encoded data # 1 transmitted by the network 3, and generates and outputs a plurality of decoded layer images Td (decoded viewpoint image TexturePic and decoded depth map DepthPic) respectively decoded.

  The image display device 4 displays all or part of the plurality of decoded layer images Td generated by the image decoding device 1. For example, in view scalable coding, a 3D image (stereoscopic image) and a free viewpoint image are displayed in all cases, and a 2D image is displayed in some cases. The image display device 4 includes a display device such as a liquid crystal display or an organic EL (Electro-luminescence) display. In addition, in spatial scalable coding and SNR scalable coding, when the image decoding device 1 and the image display device 4 have a high processing capability, an enhancement layer image with high image quality 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.

  The viewpoint image is indicated by, for example, a luminance value or a color signal value for each pixel arranged in a two-dimensional plane. Also, the depth map (also called depth map, “depth image”, “depth image”, “distance image”) corresponds to the distance from the viewpoint (photographing device, etc.) of the subject or background included in the subject space. Signal values (referred to as “depth value”, “depth value”, “depth”, etc.), and are image signals composed of signal values (pixel values) for each pixel arranged on a two-dimensional plane. The pixels constituting the depth map correspond to the pixels constituting the viewpoint image. Therefore, the depth map is a clue for representing the three-dimensional object space by using the viewpoint image which is a reference image signal obtained by projecting the object space onto the two-dimensional plane.

  Below, the image decoding apparatus 1 and the image coding apparatus 2 which concern on one Embodiment of this invention are demonstrated, referring FIGS. FIG. 3 is a functional block diagram illustrating a schematic configuration of the image decoding device 1.

The moving image decoding apparatus 1 includes encoded data # 1 in which the moving image encoding apparatus 2 encodes a layer image (one or a plurality of viewpoint images TexturePic and a depth map DepthPic corresponding to the viewpoint image TexturePic). Entered. The moving image decoding apparatus 1 decodes the input encoded data # 1 and externally outputs the layer image # 2 (one or more viewpoint images TexturePic and a depth map DepthPic corresponding to the viewpoint image TexturePic). Output. Prior to detailed description of the moving picture decoding apparatus 1, the configuration of the encoded data # 1 will be described below.
[Configuration of encoded data]
A configuration example of encoded data # 1 that is generated by the video encoding device 2 and decoded by the video decoding device 1 will be described with reference to FIG. The encoded data # 1 exemplarily includes a sequence and a plurality of pictures constituting the sequence.

  FIG. 4 shows a hierarchical structure below the sequence layer in the encoded data # 1. 4A to 4E respectively show a sequence layer that defines a sequence SEQ, a picture layer that defines a picture PICT, a slice layer that defines a slice S, a slice data layer that defines slice data, and a coding tree. It is a figure which shows the encoding unit layer which prescribes | regulates the encoding unit (Coding Unit; CU) contained in.

(Sequence layer)
In the sequence layer, a set of data referred to by the video decoding device 1 for decoding a sequence SEQ to be processed (hereinafter also referred to as a target sequence) is defined. As shown in FIG. 4A, the sequence SEQ includes a video parameter set (Sequence Parameter Set), a picture parameter set PPS (Picture Parameter Set), a picture PICT, and an additional extension. Information SEI (Supplemental Enhancement Information) is included. Here, the value indicated after # indicates the layer ID. FIG. 4 shows an example in which encoded data of # 0 and # 1, that is, layer 0 and layer 1, exists, but 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 video decoding device 1 in order to decode the target sequence is defined. For example, the width and height of the picture are defined.

  In the picture parameter set PPS, a set of encoding parameters referred to by the video decoding device 1 for decoding 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. A plurality of PPS may exist. In that case, one of a plurality of PPSs is selected from each picture in the target sequence.

(Picture layer)
In the picture layer, a set of data referred to by the video decoding device 1 for decoding a picture PICT to be processed (hereinafter also referred to as a target picture) is defined. As illustrated in FIG. 4B, the picture PICT includes slices S _{1 to} S _NS (NS is the total number of slices included in the picture PICT).

Note that, hereinafter, when it is not necessary to distinguish each of the slices S _{1 to} S _NS , the reference numerals may be omitted. The same applies to other data with subscripts included in encoded data # 1 described below.

(Slice layer)
In the slice layer, a set of data referred to by the video decoding device 1 for decoding a slice S to be processed (a slice segment, also referred to as a target slice) is defined. As shown in FIG. 4C, 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 video decoding device 1 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 that uses only intra prediction at the time of encoding, (2) P slice that uses 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.

The slice data SDATA includes one or a plurality of tree blocks TBLK _{1 to} TBLK _NC (NC is the total number of tree blocks included in the slice data SDATA).

(Tree block layer)
In the tree block layer, a set of data referred to by the video decoding device 1 for decoding a processing target tree block TBLK (hereinafter also referred to as a target tree block) is defined.

The tree block TBLK includes a tree block header TBLKH and coding unit information CU _{1 to} CU _NL (NL is the total number of coding unit information included in the tree block TBLK). Here, first, a relationship between the tree block TBLK and the coding unit information CU will be described as follows.

  Tree block TBLK is divided into units for specifying a block size for each process of intra prediction or inter prediction and transformation.

  The unit of the tree block TBLK is divided by recursive quadtree division. The tree structure obtained by this recursive quadtree partitioning is hereinafter referred to as a coding tree.

  Hereinafter, a unit corresponding to a leaf which is a node at the end of the coding tree is referred to as a coding node. In addition, since the encoding node is a basic unit of the encoding process, hereinafter, the encoding node is also referred to as an encoding unit (CU).

That is, coding unit information (hereinafter referred to as CU information) CU _{1 to} CU _NL is information corresponding to each coding node (coding unit) obtained by recursively dividing the tree block TBLK into quadtrees. is there.

  Also, the root of the coding tree is associated with the tree block TBLK. In other words, the tree block TBLK is associated with the highest node of the tree structure of the quadtree partition that recursively includes a plurality of encoding nodes.

  Note that the size of each coding node is half of the size of the coding node to which the coding node directly belongs (that is, the unit of the node one level higher than the coding node).

(Tree block header)
The tree block header TBLKH includes an encoding parameter referred to by the video decoding device 1 in order to determine a decoding method of the target tree block. Specifically, as shown in FIG. 4 (d), tree block division information SP_TBLK that specifies a division pattern of the target tree block into each CU, and a quantization parameter difference that specifies the size of the quantization step Δqp (qp_delta) is included.

  The tree block division information SP_TBLK is information representing a coding tree for dividing the tree block. Specifically, the shape and size of each CU included in the target tree block, and the position in the target tree block Is information to specify.

  The quantization parameter difference Δqp is a difference qp−qp ′ between the quantization parameter qp in the target tree block and the quantization parameter qp ′ in the tree block encoded immediately before the target tree block.

(CU layer)
In the CU layer, a set of data referred to by the video decoding device 1 for decoding a CU to be processed (hereinafter also referred to as a target CU) is defined.

  Here, before describing specific contents of data included in the CU information CU, a tree structure of data included in the CU will be described. The encoding node is a node at the root of a prediction tree (PT) and a transform tree (TT). The prediction tree and the conversion tree are described as follows.

  In the prediction tree, the encoding node is divided into one or a plurality of prediction blocks, and the position and size of each prediction block are defined.

  Prediction processing is performed for each prediction block. Hereinafter, a prediction block that is a unit of prediction is also referred to as a prediction unit (PU).

  Broadly speaking, there are two types of division in the prediction tree: intra prediction and inter prediction.

  In the case of intra prediction, there are 2N × 2N (the same size as the encoding node) and N × N division methods.

  In the case of inter prediction, there are 2N × 2N (the same size as the encoding node), 2N × N, N × 2N, N × N, and the like.

  In the transform tree, the encoding node is divided into one or a plurality of transform blocks, and the position and size of each transform block are defined.

  The conversion process is performed for each conversion block. Hereinafter, a transform block that is a unit of transform is also referred to as a transform unit (TU).

(Data structure of CU information)
Next, specific contents of data included in the CU information CU will be described with reference to FIG. As shown in FIG. 4E, the CU information CU specifically includes a skip flag SKIP, PT information PTI, and TT information TTI.

  The skip flag SKIP is a flag indicating whether or not the skip mode is applied to the target PU. When the value of the skip flag SKIP is 1, that is, when the skip mode is applied to the target CU, PT information PTI and TT information TTI in the CU information CU are omitted.

  The PT information PTI is information related to the PT included in the CU. In other words, the PT information PTI is a set of information related to each of one or more PUs included in the PT, and is referred to when the moving image decoding apparatus 1 generates a predicted image. As shown in FIG. 4D, the PT information PTI includes prediction type information PType and prediction information PInfo.

  The prediction type information PType (or CuPredMode) is information that specifies whether intra prediction or inter prediction is used as a prediction image generation method for one or a plurality of PUs included in a CU. For example, when using intra prediction, the prediction type information CuPredMode is set to MODE_INTRA indicating intra prediction, and when using inter prediction, it is set to MODE_INTER indicating inter prediction. A CU to which intra prediction is applied is called an intra CU, and a CU to which an inter CU is applied is also called an inter CU.

  The prediction information PInfo is configured from intra prediction information or inter prediction information depending on which prediction method is specified by the prediction type information PType. Hereinafter, a PU to which intra prediction is applied is also referred to as an intra PU, and a PU to which inter prediction is applied is also referred to as an inter PU.

  Further, the prediction information PInfo includes information specifying the shape, size, and position of the target PU. As described above, the generation of the predicted image is performed in units of PU. Details of the prediction information PInfo will be described later.

  The TT information TTI is information regarding the TT included in the CU. In other words, the TT information TTI is a set of information regarding each of one or a plurality of TUs included in the TT, and is referred to when the moving image decoding apparatus 1 decodes residual data. Hereinafter, a TU may be referred to as a conversion block.

As shown in FIG. 4 (d), the TT information TTI includes TT division information SP_TU that designates a division pattern of the target CU into each conversion block, and TU information TUI _{1 to} TUI _NT (NT is the target CU). The total number of transform blocks included).

  Specifically, the TT division information SP_TU is information for determining the shape and size of each TU included in the target CU and the position within the target CU. For example, the TT division information SP_TU can be realized from information (split_transform_unit_flag) indicating whether or not the target node is divided and information (trafoDepth) indicating the depth of the division.

  The TU partition information SP_TU includes information on whether or not a non-zero transform coefficient exists in each TU. For example, there is non-zero coefficient existence information (CBF; Coded Block Flag) for each TU, and for each color space, CBF for luminance luma is called cbf_luma, CBF for color difference Cb is called cbf_cb, and CBF for color difference Cr is called cbf_cr. In addition, non-zero coefficient existence information (also referred to as rqt_root_flag or no_residual_data_flag) for a plurality of TUs is included in the TU partition information SP_TU. Also, instead of encoding non-zero transform coefficients for each TU, prediction residual DC information (DC offset information) representing an average (DC) value of the prediction residual is obtained for each region or regions in the TU. An SDC flag sdc_flag indicating whether or not to perform encoding (perform region-specific DC encoding) is included. The regional DC coding is also called segment-wise DC coding (SDC). In particular, DC coding by region in intra prediction is called intra SDC, and DC coding by region in inter prediction is called inter SDC. When region-specific DC coding is applied, the CU size, PU size, and TU size may be equal.

The TU information TUI _{1 to} TUI _NT are individual information regarding each of one or more TUs included in the TT. For example, the TU information TUI includes a quantized prediction residual.

  Each quantized prediction residual is encoded data generated by the video encoding device 2 performing the following process A or process B on a target block that is a processing target block.

(Process A: When frequency conversion / quantization is performed)
Process A-1: DCT transform (Discrete Cosine Transform) of the prediction residual obtained by subtracting the prediction image from the encoding target image;
Process A-2: Quantize the transform coefficient obtained in Process A-1;
Process A-3: Variable-length encoding the transform coefficient quantized in Process A-2;
The quantization parameter qp described above represents the magnitude of the quantization step QP used when the moving image coding apparatus 2 quantizes the transform coefficient (QP = 2 ^{qp / 6} ).

(Process B: Segment-wise DC Coding (SDC))
Process B-1: An average value (DC value) of prediction residuals obtained by subtracting the prediction image from the encoding target image is calculated.

  Process B-2: Variable length coding is performed on the DC value obtained in Process B-1.

  In particular, encoding a DC value for each region is called segment-wise DC coding (SDC) and is effective for encoding a prediction residual in a flat region. For example, in depth map encoding, each depth block is used for encoding a prediction residual of a region divided into one or a plurality of regions.

(Prediction information PInfo)
As described above, there are two types of prediction information PInfo: inter prediction information and intra prediction information.

  The inter prediction information includes a coding parameter that is referred to when the video decoding device 1 generates an inter prediction image by inter prediction. More specifically, the inter prediction information includes inter PU division information that specifies a division pattern of the target CU into each inter PU, and inter prediction parameters for each inter PU.

  The inter prediction parameters include a reference image index, an estimated motion vector index, and a motion vector residual.

  On the other hand, the intra prediction information includes an encoding parameter that is referred to when the video decoding device 1 generates an intra predicted image by intra prediction. More specifically, the intra prediction information includes intra PU division information that specifies a division pattern of the target CU into each intra PU, and intra prediction parameters for each intra PU. The intra prediction parameter is a parameter for restoring intra prediction (prediction mode) for each intra PU.

  Parameters related to intra prediction (DC prediction, Planar prediction, Angular prediction) (intra prediction parameters) commonly used in coding of depth map DepthPic and texture TexturePic are flags related to MPM (Most Probable Mode, the same applies hereinafter). A certain mpm_flag, mpm_idx that is an index for selecting an MPM, and rem_idx that is an index (residual prediction mode index) for specifying a prediction mode other than the MPM are included. Further, in the following, when simply described as “prediction mode”, it indicates the luminance prediction mode. The color difference prediction mode is described as “color difference prediction mode” and is distinguished from the luminance prediction mode. The parameter for restoring the prediction mode includes chroma_mode that is a parameter for designating the color difference prediction mode. Note that mpm_flag and rem_idx correspond to “prev_intra_luma_pred_flag” (SYN02 in FIG. 5 (a)) and “rem_intra_luma_pred_mode” (SYN03 in FIG. 5 (a)) in Non-Patent Document 1, respectively. Further, chroma_mode corresponds to “intra_chroma_pred_mode” (not shown).

  Parameters (depth intra prediction parameters, DMM prediction mode information) for restoring the prediction mode (intra extended mode (SYN01 in Fig. 5 (a))) for depth intra prediction (DMM prediction) used for depth map encoding Includes a flag indicating the presence / absence of depth intra prediction (depth intra prediction presence / absence flag) dim_not_present_flag (SYN01A in FIG. 5 (b)), a depth intra prediction method (DMM1 prediction based on wedgelet division (INTRA_DMM_WFULL) and contour division) DMM4 prediction (INTRA_DMM_CREDTEX)) flag (depth intra mode flag) depth_intra_mode_flag (SYN01B in FIG. 5 (b)) and an index (wedgelet pattern) that specifies a wedgelet pattern representing a partition pattern in the PU in DMM1 prediction Index) wedge_full_tab_idex (SYN01C in FIG. 5B).

  Further, the prediction parameters related to intra SDC, inter SDC, and depth intra prediction further include DC offset information for correcting the depth prediction value of one or two divided areas in the PU, that is, whether or not there is a DC offset. There is a flag depth_dc_flag (SYND1 in FIG. 6), depth_dc_abs (SYND02 in FIG. 6) indicating the absolute value of the DC offset value, and depth_dc_sign_flag (SYND03 in FIG. 6) indicating the sign of the DC offset value.

[Video decoding device]
Below, the structure of the moving image decoding apparatus 1 which concerns on this embodiment is demonstrated with reference to FIGS.

(Outline of video decoding device)
The video decoding device 1 generates a predicted image for each PU, generates a decoded image # 2 by adding the generated predicted image and a prediction residual decoded from the encoded data # 1, and generates The decoded image # 2 is output to the outside.

  Here, the generation of the predicted image is performed with reference to an encoding parameter obtained by decoding the encoded data # 1. An encoding parameter is a parameter referred in order to generate a prediction image. In addition to prediction parameters such as a motion vector referred to in inter prediction and a prediction mode referred to in intra prediction, the encoding parameters include PU size and shape, block size and shape, and original image and predicted image. And residual data. Hereinafter, a set of all information excluding the residual data among the information included in the encoding parameter is referred to as side information.

  Also, in the following, a picture (frame), a slice, a tree block, a CU, a block, and a PU to be decoded are a target picture, a target slice, a target tree block, a target CU, a target block, and a target PU, respectively. I will call it.

  The size of the tree block is, for example, 64 × 64 pixels, the size of the CU is, for example, 64 × 64 pixels, 32 × 32 pixels, 16 × 16 pixels, and 8 × 8 pixels, and the size of the PU is For example, 64 × 64 pixels, 32 × 32 pixels, 16 × 16 pixels, 8 × 8 pixels, 4 × 4 pixels, and the like. However, these sizes are merely examples, and the sizes of the tree block, CU, and PU may be other than the sizes shown above.

(Configuration of video decoding device)
Referring to FIG. 3 again, the schematic configuration of the video decoding device 1 will be described as follows. FIG. 3 is a functional block diagram illustrating a schematic configuration of the video decoding device 1.

  As shown in FIG. 3, the video decoding device 1 includes a variable length decoding unit 11, an inverse quantization / inverse conversion unit 13, a predicted image generation unit 14, an adder 15, and a frame memory 16.

[Variable length decoding unit]
The variable length decoding unit 11 decodes various parameters included in the encoded data # 1 input from the video decoding device 1. In the following description, it is assumed that the variable length decoding unit 11 appropriately decodes a parameter encoded by an entropy encoding method such as CABAC. Specifically, the variable length decoding unit 11 decodes encoded data # 1 for one frame according to the following procedure.

  First, the variable length decoding unit 11 demultiplexes the encoded data # 1 for one frame into various information included in the hierarchical structure shown in FIG. For example, the variable length decoding unit 11 refers to information included in various headers and sequentially separates the encoded data # 1 into slices and tree blocks.

  Here, the various headers include (1) information about the method of dividing the target picture into slices, and (2) information about the size, shape, and position of the tree block belonging to the target slice. .

  Then, the variable length decoding unit 11 divides the target tree block into CUs with reference to the tree block division information SP_TBLK included in the tree block header TBLKH. Further, the variable length decoding unit 11 decodes the TT information TTI related to the conversion tree obtained for the target CU and the PT information PTI related to the prediction tree obtained for the target CU.

  The variable length decoding unit 11 supplies the TT information TTI obtained for the target CU to the TU information decoding unit 12. Further, the variable length decoding unit 11 supplies the PT information PTI obtained for the target CU to the predicted image generation unit 14. The TT information TTI includes the TU information TUI corresponding to the TU included in the conversion tree as described above. Further, as described above, the PT information PTI includes PU information PUI (prediction information Info of each PU) corresponding to each PU included in the target prediction tree.

  In the following, decoding processing of intra prediction parameters included in intra PU prediction information Pinfo, which is deeply related to the present invention, and DC offset information used for regional DC coding (intra SDC, inter SDC) and depth intra prediction An outline will be described.

(Intra prediction parameters)
The variable length decoding unit 11 decodes each syntax from the encoded data # 1 according to the syntax table of the intra prediction mode extension intra_mode_ext () shown in SYN01 of FIG. In the decoding target layer, a flag indicating whether or not DMM1 prediction is possible in the depth encoding tool (DMM1 prediction mode availability flag) intra_sdc_dmm_wfull_flag is 1, or a flag indicating whether or not DMM4 prediction is possible in the decoding target layer (DMM4 prediction mode availability flag) Intra prediction mode extension intra_mode_ext () is decoded when dmm_cpredtex_flag is 1. When DMM1 prediction mode enable / disable flag intra_sdc_dmm_wfull_flag is 1, DMM1 prediction mode that is a depth encoding tool can be applied in the decoding target layer. The DMM4 prediction mode availability flag dmm_cpredtex_flag indicates that the DMM4 prediction mode, which is a depth coding tool, can be applied in the decoding target layer, and is 0. In the case of DMM1 prediction mode. Availability flag, and DMM4 prediction mode permission flag parameter set (video parameter set VPS, sequence parameter set SPS, a picture parameter set PPS, slice header SH) is decoded from the like.

  First, when the target PU size is 32 × 32 or less (logPbSize <6), the variable length decoding unit 11 decodes the depth intra prediction presence / absence flag dim_not_present_flag (SYN01A in FIG. 5B). When the target PU size is larger than 32 × 32, the value of the flag is estimated as 1. This flag is a flag indicating the presence / absence of depth intra prediction. When the value of the flag is 1, the depth intra prediction mode flag depth_intra_mode_flag related to the target PU is not included in the encoded data, and the intra prediction mode numbers' 0 'to' This indicates that any intra prediction method of 34 ′ (DC prediction, Planar prediction, Angular prediction) is used for the target PU. Moreover, when the flag is 0, it indicates that the depth intra prediction mode depth_intra_mode_flag is in the encoded data.

  The variable length decoding unit 11 derives the DMM flag DmmFlag of the target PU based on the decoded depth intra prediction presence / absence flag dim_not_present_flag by the following equation.

DmmFlag =! Dim_not_present_flag
That is, the logical negation value of the depth intra prediction presence / absence flag is set in the DMM flag. When the DMM flag is 1, it indicates that depth intra prediction is used, and when the DMM flag is 0, it indicates that depth intra prediction is not used.

(When the depth intra prediction presence / absence flag is 1)
When the depth intra prediction presence / absence flag dim_not_present_flag is 1, the variable length decoding unit 11 further decodes the depth intra mode flag depth_intra_mode_flag. The flag is a flag related to selection of a depth intra prediction method. When the flag is 0, it indicates that the depth intra prediction is DMM1 prediction. When the flag is 1, it indicates that the depth intra prediction is DMM4 prediction.

  When the depth intra mode flag depth_intra_mode_flag is 0, that is, when the depth intra prediction is DMM1 prediction, the variable length decoding unit 11 sets a prediction mode number indicating DMM1 prediction to the prediction mode predModeIntra. Further, the wedgelet pattern index wedge_full_tab_idx that specifies the wedgelet pattern indicating the division pattern in the PU is decoded.

  When the depth intra mode flag depth_intra_mode_flag is 1, that is, when the depth intra prediction is DMM4 prediction, the variable length decoding unit 11 sets a prediction mode number indicating DMM4 prediction to the prediction mode predModeIntra.

(If the depth intra prediction flag is 0)
When the depth intra prediction presence / absence flag dim_not_present_flag is 0, the variable length decoding unit 11 decodes the MPM flag mpm_flag indicating whether or not the intra prediction mode of the target PU matches the estimated prediction mode MPM. When the flag is 1, it indicates that the intra prediction mode of the target PU matches the estimated prediction mode MPM. When the flag is 0, the prediction mode numbers “0” to “34” (DC prediction, Planar prediction, Angular Among any prediction), this indicates any prediction mode except the estimated prediction mode MPM.

  When the MPM flag is 1, the variable length decoding unit 11 further decodes the MPM index mpm_idx designating the estimated prediction mode MPM, and sets the estimated prediction mode indicated by the mpm_idx to the prediction mode predModeIntra.

  When the MPM flag is 0, the variable length decoding unit 11 further decodes an index rem_idx for designating a prediction mode other than the MPM, and is a prediction mode number excluding the estimated prediction mode MPM identified from the rem_idx. Any prediction mode number among 0 'to' 34 '(DC prediction, Planar prediction, Angular prediction) is set to the prediction mode predModeIntra.

(DC offset information)
The variable length decoding unit 11 further includes a DC offset information decoding unit 111 (not shown), and the DC offset information decoding unit 111 decodes the DC offset information included in the target CU.

  More specifically, the DC offset information decoding unit 111 derives a CU DC offset information presence / absence flag cuDepthDcPresentFlag indicating the presence / absence of DC offset information in the target CU by the following equation.

cuDepthDcPresentFlag = (sdc_flag || (CuPredMode == MODE_INTRA))
That is, when the SDC flag sdc_flag is 1 or when the prediction type information CuPredMode is intra prediction, the intra-CU DC offset information presence / absence flag is set to 1 (true), and in other cases (SDC flag is 0 (false) ) And inter prediction) is set to 0 (false). When the intra-CU DC offset information presence / absence flag is 1, it indicates that DC offset information can exist in the target CU. When the flag is 0, it indicates that no DC offset information exists in the target CU.

  Subsequently, when the intra-CU DC offset information presence / absence flag is 1, the DC offset information decoding unit 111 corrects the depth prediction value of the region divided into one or more in the PU for each PU in the target CU. DC offset information for decoding is decoded.

  More specifically, first, the DC offset information decoding unit 111 derives an intra-PU DC offset information presence / absence flag puDepthDcPresentFlag indicating whether or not DC offset information related to the target PU can exist.

puDepthDcPresentFlag = (DmmFlag || sdc_flag)
That is, when the DMM flag of the target PU is 1 or the SDC flag is 1, the intra-PU DC offset information presence / absence flag is set to 1 (true), otherwise (DmmFlag == 0 && sdc_flag == 0) Is set to 0 (false). When the DC offset information flag in PU is 1, it indicates that DC offset information can exist in the target PU, and when the flag is 0, it indicates that DC offset information does not exist in the target PU.

(When the DC offset information presence flag in PU is 1)
The DC offset information decoding unit 111 derives the number of divided areas dcNumSeg of the target PU based on the DMM flag of the target PU by the following formula.

dcNumSeg = DmmFlag? 2: 1
That is, when the DMM flag is 1, the number of divided areas dcNumSeg of the target PU is set to 2, and when the DMM flag is 0, dcNumSeg is set to 1.

  Subsequently, when the target PU is applied with intra SDC (CuPredMode == MODE_INTRA && sdc_flag == 1), the DC offset information decoding unit 111 indicates the presence / absence of DC offset information corresponding to the number of divided regions dcNumSeg in the target PU. The DC offset information presence / absence flag depth_dc_flag is decoded from the encoded data. In other cases, the DC offset information presence / absence flag depth_dc_flag is estimated as 1. When the DC offset information presence / absence flag is 1, DC offset information (depth_dc_abs [i], depth_dc_sing_flag [i] (i = 0..dcNumSeg-1)) corresponding to the number of divided regions dcNumSeg is encoded in the target PU. When the DC offset information flag is 0, it indicates that there is no DC offset information in the encoded data.

  Subsequently, when the DC offset presence / absence flag depth_dc_flag is 1, the DC offset information decoding unit 111 further determines the absolute value (DC) of the DC offset value for each divided region Ri (i = 0..dcNumSeg-1) of each PU. Depth_dc_abs [i] indicating the offset absolute value) and depth_dc_sign_flag [i] indicating the positive / negative sign of the DC offset value are decoded. Note that the DC offset information decoding unit 111 encodes depth_dc_sign_flag [i] indicating positive / negative coding of the DC offset value when the DC offset absolute value (depth_dc_abs [i] + dcNumSeg−2) is greater than 0 (or more). When the DC offset absolute value (depth_dc_abs [i] + dcNumSeg-2) is 0 or less (less than), the depth_dc_sign_flag is estimated to be 0.

  Subsequently, the DC offset information decoding unit 111 performs each based on the DC offset information (DC offset information presence / absence flag depth_dc_flag, DC offset absolute value depth_dc_abs [i], DC offset code depth_dc_sign_flag [i]), and the number of divided regions dcNumSeg. A DC offset value DcOffset [i] corresponding to the divided region Ri (i = 0..dcNumSeg-1) in the PU is derived by the following equation.

DcOffset [i] =! Depth_dc_offset_flag? 0:
(1 -2 * depth_dc_sign_flag [i]) * (depth_dc_abs [i] + dcNumSeg-2)
That is, when the DC offset information presence / absence flag is 0, the DC offset value DcOffset [i] of the divided region Ri is set to 0, and when the DC offset information presence / absence flag is 1, depth_dc_sign_flag [i], depth_dc_abs [i] Based on the number of divided areas dcNumSeg, the DC offset value DcOffset [i] of the divided area Ri is set. The advantage of the above derivation formula is that when the DC offset information presence / absence flag is 0, the DC offset value derivation process based on depth_dc_sign_flag [i], depth_dc_abs [i], and the number of divided regions dcNumSeg can be omitted. It is.

  Note that the derivation formula of the DC offset value is not limited to the above, and can be changed within a practicable range. For example, the DC offset value may be derived from the following equation.

DcOffset [i] =
(1-2 * depth_dc_sign_flag [i]) * (depth_dc_abs [i] + dcNumSeg-2)

[Inverse quantization / inverse transform unit]
The inverse quantization / inverse transform unit 13 performs an inverse quantization / inverse transform process on each block included in the target CU based on the TT information TTI. Specifically, for each target TU, the inverse quantization / inverse transform unit 13 performs inverse quantization and inverse orthogonal transform on the quantized prediction residual included in the TU information TUI corresponding to the target TU, thereby performing the target TU. The prediction residual D (or resSamples [x] [y]) for each pixel corresponding to is restored. Here, the orthogonal transform refers to an orthogonal transform from the pixel region to the frequency region. Therefore, the inverse orthogonal transform is a transform from the frequency domain to the pixel domain. Examples of inverse orthogonal transform include inverse DCT transform (Inverse Discrete Cosine Transform), inverse DST transform (Inverse Discrete Sine Transform), and the like. The inverse quantization / inverse transform unit 13 supplies the restored prediction residual D to the adder 15. Note that, when the SDC flag is 1, the inverse quantization / inverse transformation unit 13 omits the inverse quantization / inverse transformation process, and the prediction residual D (or resSamples [x] [y]) for each pixel of the target TU. Is set to 0 and supplied to the adder 15.

[Predicted image generator]
The predicted image generation unit 14 generates a predicted image based on the PT information PTI for each PU included in the target CU. Specifically, the predicted image generation unit 14 is a decoded image by performing intra prediction or inter prediction for each target PU according to the parameters included in the PU information PUI (prediction information Info) corresponding to the target PU. A predicted image Pred is generated from the locally decoded image P ′. The predicted image generation unit 14 supplies the generated predicted image Pred to the adder 15. The configuration of the predicted image generation unit 14 will be described in more detail later.

[Adder]
The adder 15 adds the predicted image Pred supplied from the predicted image generation unit 14 and the prediction residual D supplied from the inverse quantization / inverse transform unit 13, thereby obtaining the decoded image P for the target CU. Generate.

[Frame memory]
The decoded image P that has been decoded is sequentially recorded in the frame memory 16. In the frame memory 16, at the time of decoding the target tree block, decoded images corresponding to all tree blocks decoded before the target tree block (for example, all tree blocks preceding in the raster scan order) are stored. It is recorded.

  Also, at the time of decoding the target CU, decoded images corresponding to all the CUs decoded before the target CU are recorded.

  In the video decoding device 1, the encoded data for one frame input to the video decoding device 1 at the time when the decoded image generation processing for each tree block is completed for all tree blocks in the image. Decoded image # 2 corresponding to # 1 is output to the outside.

(Definition of prediction mode)
As described above, the predicted image generation unit 14 generates and outputs a predicted image based on the PT information PTI. When the target CU is an inter CU, the PU information PTI input to the predicted image generation unit 14 is, for example, a motion vector mvLX (X = 0, 1) and a decoded image stored in the frame memory 16 as a reference image. It includes an inter prediction identifier inter_pred_idx that specifies an inter prediction method such as a reference image index refIdxLX (X = 0, 1), single prediction (L0 prediction, L1 prediction), or bi-directional prediction.

  When the target CU is an intra CU, the PU information PTI input to the predicted image generation unit 14 includes a prediction mode (IntraPredMode) and a color difference prediction mode (IntraPredModeC). Hereinafter, the definition of the prediction mode (luminance / color difference) will be described with reference to FIGS.

(Overview)
FIG. 7 shows an example of prediction mode numbers corresponding to the classification of intra prediction schemes used in the video decoding device 1. Planar prediction (INTRA_PLANAR) is '0', DC prediction (INTRA_DC) is '1', Angular prediction (INTRA_ANGULAR) is '2' to '34', DMM1 prediction (INTRA_DMM_WFULL) is '35', DMM4 prediction (INTRA_DMM_CREDTEX) A prediction mode number of “36” is assigned. Further, the DMM1 prediction and the DMM4 prediction are collectively referred to as depth intra prediction. Depth intra prediction is based on a depth model in which a target block (also referred to as a depth block) on a depth map is composed of two non-rectangular flat regions, and the depth value of each flat region is expressed by a fixed value. Yes. The depth model is composed of partition information indicating the region to which each pixel belongs, and depth value information of each region. In the DMM prediction, depth block division methods include wedgelet partition called DMM1 and contour partition called DMM4. Details of the depth intra prediction will be described later.

  Next, the identifier of each prediction mode included in the direction prediction will be described with reference to FIG. FIG. 8 shows prediction directions corresponding to the prediction mode identifiers for 33 types of prediction modes belonging to the direction prediction.

(Details of predicted image generator)
Next, the configuration of the predicted image generation unit 14 will be described in more detail with reference to FIG. FIG. 9 is a functional block diagram illustrating a configuration example of the predicted image generation unit 14. In addition, this structural example has illustrated the functional block which concerns on the prediction image production | generation of intra CU among the functions of the prediction image production | generation part 14. FIG.

  As illustrated in FIG. 9, the predicted image generation unit 14 includes a prediction unit setting unit 141, a reference pixel setting unit 142, a switch 143, a reference pixel filter unit 144, and a predicted image derivation unit 145.

  The prediction unit setting unit 141 sets PUs included in the target CU as target PUs in a prescribed setting order, and outputs information related to the target PU (target PU information). The target PU information includes at least the size nS of the target PU, the position of the target PU in the CU, and the index (luminance color difference index cIdx) indicating the luminance or color difference plane of the target PU.

  The reference pixel setting unit 142 reads a pixel value (decoded pixel value) of a decoded image around the target PU recorded in the frame memory based on the input target PU information, and is a reference pixel referred to when a predicted image is generated Set. The reference pixel value p [x] [y] is set by the following equation using the decoded pixel value r [x] [y].

p [x] [y] = r [xB + x] [yB + y] x = -1, y = -1 .. (nS * 2-1) and x = 0 .. (nS * 2- 1), y = -1
Here, (xB, yB) represents the position of the upper left pixel in the target PU, nS represents the size of the target PU, and indicates the larger value of the width or height of the target PU. In the above equation, basically, the decoded pixel value included in the decoded pixel line adjacent to the upper side of the target PU and the decoded pixel column adjacent to the left side of the target PU is copied to the corresponding reference pixel value. Note that if there is no decoded pixel value corresponding to a specific reference pixel position or reference cannot be made, a predetermined value, for example, 1 << (BitDepth-1) may be used. Here, BitDepth is the bit depth of the pixel. In addition, instead of the predetermined value, a referable decoded pixel value existing in the vicinity of the corresponding decoded pixel value may be used.

  The switch 143 outputs the reference pixel to the corresponding output destination based on the luminance color difference index cIdx and the prediction mode predModeIntra among the input target PU information. More specifically, the luminance color difference index cIdx is 0 (the pixel to be processed is luminance), and the prediction mode predModeIntra is 0 to 34 (the prediction mode is Planar prediction or DC prediction, Alternatively, when Angular prediction is performed (predModeIntra <35), the switch 143 outputs the input reference pixel to the reference pixel filter unit 144. In other cases, that is, the luminance color difference index cIdx is 1 (the pixel to be processed is a color difference) or the prediction mode predModeIntra is assigned to the prediction mode numbers '35' to '36'. When (predModeIntra> = 35) (DMM1 prediction or DMM4 prediction), the switch 143 outputs the input reference pixel to the predicted image deriving unit 145.

  The reference pixel filter unit 144 applies a filter to the input reference pixel value, and outputs the reference pixel value after the filter application. Specifically, the reference pixel filter unit 144 determines whether to apply the filter according to the target PU size and the prediction mode predModeIntra.

  The predicted image deriving unit 145 generates and outputs a predicted image predSamples of the target PU based on the input PU information (prediction mode predModeIntra, luminance color difference index cIdx, PU size nS) and the reference pixel p [x] [y]. To do. Detailed description of the predicted image deriving unit 145 will be described later.

(Flow of predicted image generation processing)
Next, an outline of the predicted image generation processing for each CU in the predicted image generation unit 14 will be described with reference to the flowchart of FIG. When the predicted image generation processing for each CU starts, first, the prediction unit setting unit 141 sets one of the PUs included in the CU as the target PU according to a predetermined order, and sets the target PU information as the reference pixel setting unit 142 and the switch. It outputs to 143 (S11). Next, the reference pixel setting unit 142 sets the reference pixel of the target PU using the decoded pixel value read from the external frame memory (S12). Next, the switch 143 determines whether the target PU is luminance or color difference based on the input target PU information, or whether the prediction mode predModeIntra is DMM prediction, and switches the output according to the determination result ( S13).

  When the target PU is luminance and the prediction mode predModeIntra is not depth intra prediction (cIdx == 0 && predModeIntra <35) (YES in S13), the output of the switch 143 is connected to the reference pixel filter unit 144. Subsequently, the reference pixel is input to the reference pixel filter unit 144, the reference pixel filter is applied according to the prediction mode separately input, and the reference pixel after the filter application is output to the predicted image derivation unit 145 (S14). ).

  On the other hand, when the target PU is a color difference or the prediction mode predModeIntra is depth intra prediction (cIdx == 1 || predModeIntra> = 35) (NO in S13), the output of the switch 143 is sent to the prediction image deriving unit 145. Connected.

  Next, the predicted image derivation unit 145 generates predicted images predSamples in the target PU based on the input PU information (prediction mode predModeIntra, luminance color difference index cIdx, PU size nS) and the reference pixel p [x] [y]. And output (S15).

  When the generation of the prediction image of the luminance or color difference of the target PU is completed, the prediction unit setting unit 141 determines whether the prediction images of all the PUs in the target CU have been generated (S16). When the prediction image of some PUs in the target CU has not been generated (NO in S16), the process returns to S1, and the prediction image generation process for the next PU in the target CU is executed. If predicted images of all PUs in the target CU have been generated (YES in S16), the predicted images of the luminance and color difference of each PU in the target CU are combined and output as a predicted image of the target CU, and the process ends. To do.

(Details of predicted image deriving unit 145)
Next, details of the predicted image deriving unit 145 will be described. As illustrated in FIG. 9, the predicted image derivation unit 145 further includes a DC prediction unit 145D, a Planar prediction unit 145P, an Angular prediction unit 145A, and a DMM prediction unit 145T.

  The predicted image deriving unit 145 selects a prediction method used for generating a predicted image based on the input prediction mode predModeIntra. The selection of the prediction method is realized by selecting a prediction method corresponding to the prediction mode number of the input prediction mode predModeIntra based on the definition of FIG.

  Further, the predicted image deriving unit 145 derives a predicted image corresponding to the prediction method selection result. More specifically, the prediction image deriving unit 145, when the prediction method is Planar prediction, DC prediction, Angular prediction, and DMM prediction, respectively, Planar prediction unit 145P, DC prediction unit 145D, Angular prediction unit 145A, and A predicted image is derived by the DMM prediction unit 145T.

  The DC prediction unit 145D derives a DC prediction value corresponding to the average value of the pixel values of the input reference pixels, and outputs a prediction image using the derived DC prediction value as a pixel value.

  The Planar prediction unit 145P generates and outputs a prediction image based on pixel values derived by linearly adding a plurality of reference pixels according to the distance to the prediction target pixel.

[Angular prediction unit 145A]
The Angular prediction unit 145A generates and outputs a prediction image corresponding to the target PU using reference pixels in a prediction direction (reference direction) corresponding to the input prediction mode predModeIntra. In the process of generating a predicted image by Angular prediction, main reference pixels are set according to the value of the prediction mode predModeIntra, and the predicted image is generated with reference to the main reference pixels in units of lines or columns in the PU.

[DMM prediction unit 145T]
The DMM prediction unit 145T generates and outputs a prediction image corresponding to the target PU based on DMM prediction (also referred to as depth modeling mode or depth intra prediction) corresponding to the input prediction mode predModeIntra.

  Prior to detailed description of the DMM prediction unit 145T, an outline of DMM prediction will be described with reference to FIG. FIG. 14 is a conceptual diagram of DMM prediction executed in the DMM prediction unit 145T. As shown in FIG. 14A, the depth map mainly has an edge region representing an object boundary and a flat region (substantially constant depth value) representing an object area. First, in the DMM prediction, basically, using the image feature of the depth map, the target block is divided into two regions R0 and R1 along the edge of the object, and as shown in FIG. A wedgelet pattern WedgePattern [x] [y], which is pattern information indicating a region to which each pixel belongs, is derived.

  Wedgelet pattern WedgePattern [x] [y] is a matrix with the size of the target block (target PU) width x height, and 0 or 1 is set for each element (x, y), and the target It indicates which of the two regions R0 and R1 each pixel of the block belongs to. In the example of FIG. 14B, if the element value is 0, it belongs to the region R0, and if it is 1, it belongs to the region R1. Next, as shown in FIG. 14C, a prediction image is generated by filling each of the regions R0 and R1 with depth prediction values.

  Hereinafter, the configuration of the DMM prediction unit 145T will be described with reference to FIG. FIG. 11 is a functional block diagram showing a configuration example of the DMM prediction unit 145T.

  As shown in FIG. 11, a DC predicted image derivation unit 145T1, a DMM1 wedgelet pattern generation unit 145T2, and a DMM4 wedgelet pattern generation unit 145T3 are provided.

  The DMM prediction unit 145T activates the wedgelet pattern generation means (DMM1 wedgelet pattern generation unit, DMM4 wedgelet pattern generation unit) corresponding to the input prediction mode predModeIntra, and the wedgelet pattern wedgePattern indicating the division pattern of the target PU Generate [x] [y]. More specifically, when the prediction mode predModeIntra is the prediction mode number “35”, that is, in the INTRA_DMM_WEDGEFULL mode, the DMM1 wedgelet pattern generation unit 145T2 is activated. On the other hand, when the prediction mode predModeIntra is the prediction mode number “36”, that is, in the INTRA_DMM_CPCREDTEX mode, the DMM4 wedgelet pattern generation unit 145T3 is activated. Thereafter, the DMM prediction unit 145T activates the DC prediction image derivation unit 145T1 to acquire a prediction image of the target PU.

Example 1
[DC predicted image deriving unit 145T1]
The DC predicted image derivation unit 145T1 roughly divides the target PU into two regions based on the wedgelet pattern wedgePattern [x] [y] of the target PU (for example, the region shown in FIG. 14C) R0, R1), the input PT information, and the reference pixel p [x] [y] based on the prediction value for the region R0 and the prediction value for the region R1, and the prediction value derived for each region is predicted image Derived by setting predSamples [x] [y].

  Hereinafter, the configuration of the DC predicted image deriving unit 145T1 will be described with reference to FIG. As illustrated in FIG. 1, the DC predicted image deriving unit 145T1 further includes an edge flag deriving unit 146, a DC predicted value deriving unit 147, and a predicted image deriving unit 148.

[Edge flag deriving unit 146]
The edge flag deriving unit 146 determines the division direction of the input wedgelet pattern wedgePattern [x] [y] (x = 0..nS-1, y = 0..nS-1). The left uppermost element wedgePattern [0] [0] of the let pattern (corresponding to the upper leftmost pixel of the target PU), the upper rightmost element wedgePattern [nS-1] [0] (corresponding to the upper rightmost pixel of the target PU), the lower leftmost element With reference to wedgePattern [0] [nS-1] (corresponding to the lower leftmost pixel of the target PU), the vertical edge flag vertEdgeFlag and the horizontal edge flag horEdgeFlag are respectively expressed by the following equations (eq.1) and (eq.2) Derived by The derived vertical edge flag vertEdgeFlag and horizontal edge flag horEdgeFlag are supplied to the DC prediction value deriving unit 147.

vertEdgeFlag = (wedgePattern [0] [0]! = wedgePattern [nS-1] [0]) (eq.1)
horEdgeFlag = (wedgePattern [0] [0]! = wedgePattern [0] [nS-1]) (eq.2)
That is, when the values of the upper leftmost element wedgePattern [0] [0] and the uppermost rightmost element wedgePattern [nS-1] [0] of the wedgelet pattern are equal, the vertical edge flag vertEdgeFlag is set to 0. Set. When the vertical edge flag vertEdgeFlag is 1, it means that there is a division boundary (perpendicular boundary) on the upper side of the target PU, and when it is 0, it means that there is no division boundary on the upper side of the target PU.

  Similarly, when the values of the wedget pattern upper left element wedgePattern [0] [0] and lower left element wedgePattern [0] [nS-1] are equal, the horizontal edge flag horEdgeFlag is set to 0 and they are not equal 1 is set. When the horizontal edge flag horEdgeFlag is 1, it means that there is a division boundary (horizontal boundary) on the left side of the target PU, and when it is 0, there is no division boundary on the left side of the target PU (block). means. Here, if there is a division boundary on the X side (X = up, right, left, bottom) of the target PU, the value (pattern value) of the wedgelet pattern wedgePattern [x] [y] on the X side is It refers to a boundary that changes from 0 to 1 or from 1 to 0.

  Based on the state of the vertical edge flag vertEdgeFlag and the horizontal edge flag horEdgeFlag, it is possible to grasp the division pattern of the target PU.

  With reference to FIG. 12, an example of a division pattern indicated by the state of the vertical edge flag vertEdgeFlag and the horizontal edge flag horEdgeFlag is shown. 12A to 12D, the region R0 on the block is a set of elements having the same pattern value as the upper left element wedgePattern [0] [0], and the region R1 is the upper left element wedgePattern. [0] A set of elements having pattern values different from [0].

  FIG. 12A shows a division pattern indicated by (vertEdgeFlag, horEdgeFlag) = (0, 0), and the division boundaries are on the right side and the lower side as in the block PA1.

  FIG. 12B is a division pattern indicated by (vertEdgeFlag, horEdgeFlag) = (1,0), and the division boundary is on the upper side and the lower side as in the block PB1, or on the upper side and the right side as in the block PB2. is there.

  FIG. 12C shows a division pattern indicated by (vertEdgeFlag, horEdgeFlag) = (0, 1), and the division boundary is on the left side and the right side as in the block PC1, or on the left side and the bottom side as in the block PC2. is there.

  FIG. 12D shows a division pattern indicated by (vertEdgeFlag, horEdgeFlag) = (1, 1), and the division boundaries are on the upper side and the left side as in the block PD1.

[DC predicted value deriving unit 147]
The DC prediction value derivation unit 147 assigns the DC prediction values dcValLT and dcValBR to be assigned to the two regions divided from the reference pixel p [x] [y] according to the input vertical edge flag vertEdgeFlag and horizontal edge flag horEdgeFlag. To derive. For convenience, a region composed of elements having the same value as the upper leftmost element wedgePattern [0] [0] of the wedgelet pattern has a value different from the region R0 (first region) and the uppermost left element wedgePattern [0] [0]. It is assumed that a region composed of elements is a region R1 (second region), a DC predicted value related to the region R0 is dcValLT, and a DC predicted value related to the region R1 is dcValBR.

  (1) When the vertical edge flag vertEdgeFlag is equal to the horizontal edge flag horEdgeFlag (vertEdgeFlag == horEdgeFlag, division patterns (a) and (d) in FIG. 12), each DC prediction value is derived by the following procedure. .

  As shown in FIG. 13A, the DC predicted value deriving unit 147 uses the following equation (eq.3) to calculate the left uppermost pixel ((x, y) = (0,0)) of the target PU, and The average value of the reference pixel p [-1] [0] and the reference pixel p [0] [-1] adjacent on the upper side is set to dcValLT.

dcValLT = (p [-1] [0] + p [0] [-1]) >> 1 (eq.3)
Similarly, the reference pixel p [-1] [2] in the x direction -1 and the y direction (2 * nS-1) with the upper left pixel of the target PU as a reference by the following equation (eq.4) * nS-1] and the reference pixel p [2 * nS-1] [-1] in the x direction (2 * nS-1) and the y direction -1 based on the upper left pixel of the target PU Set the average value to dcValBR.

dcValBR = (p [-1] [2 * nS-1] + p [2 * nS-1] [-1]) >> 1 (eq.4)
Here, in the case of the division pattern shown in FIG. 12 (a) or (d), considering the boundary dividing the region R0 and the region R1 (for example, the line L in FIG. 13 (a)), in many cases, the region A reference pixel that is likely to belong to R1 is considered to be a reference pixel that is farthest from the region R0. Therefore, as the reference pixel of the region R1, among the reference pixels on the upper side of the target PU, the point p [2 * nS-1] [-1] away from the region R0 and the reference pixels on the left side of the target PU It is preferable to use a point p [-1] [2 * nS-1] away from the region R0 and take an average value to reduce noise.

  In the prior art, the reference pixels used for derivation of the DC prediction value of the region R0 are the same in the division patterns shown in FIGS. 12A and 12D, but are used for derivation of the DC prediction value of the region R1. Since different reference pixels are used, the DC prediction value derivation process for the region R1 cannot be shared by the two division patterns. On the other hand, in the present embodiment, it is possible to share the DC prediction value derivation process by using the same reference pixel for each of the regions R0 and R1. That is, it is not necessary to distinguish FIG. 12 (a) and FIG. 12 (d). Also, without calculating the pixel intensity (pixel difference) between the reference pixels, the reference pixel is selected based on only the horizontal edge flag and the vertical edge flag, and the DC predicted values dcValLT and dcValBR of each region are derived. It is possible. That is, it is possible to perform clustering of block division patterns necessary for DC predicted value calculation only by accessing a wedgelet pattern without accessing a depth image that is a reference pixel.

  In the embodiment, as a reference pixel used when deriving the DC predicted value dcValBR of the region R1, a reference pixel having coordinates (x, y) = (2 * nS-1, -1) on the upper side of the target PU p [2 * nS-1] [-1] and the reference pixel p [-1] [2 * nS- of the coordinates (x, y) = (-1, 2 * nS-1) on the left side of the target PU 1], but is not limited to this. For example, the reference pixel p [xL] [-1] at another coordinate (xL, -1) on the upper side of the target PU, and the reference pixel p [-at another coordinate (-1, yT) on the left side of the target PU 1] [yT], xL = nS.. 2 * nS-1, yT = nS .. 2 * nS-1 may be set.

  (2) When the vertical edge flag vertEdgeFlag and the horizontal hedge flag horEdgeFlag are different (vertEdgeFlag! = HorEdgeFlag, division patterns (b) and (c) in FIG. 12), the DC predicted value derivation unit 147 uses the following equation (eq .5) to (eq.6) are used to derive each DC prediction value.

dcValLT = horEdgeFlag? p [(nS-1) >> 1] [-1]: p [-1] [(nS-1) >> 1] (eq.5)
dcValBR = horEdgeFlag? p [-1] [nS]: p [nS] [-1] (eq.6)
That is, when the horizontal edge flag horEdgeFlag is 1 (vertical edge flag vertEdgeFlag is 0), the DC prediction value deriving unit 147 is adjacent to the center pixel on the upper side of the target PU as shown in FIG. The reference pixel p [(nS-1) >> 1] [-1] to be used is the DC predicted value dcValLT of the region R0, and the reference pixel p [-1] [nS] adjacent to the lower left of the lower leftmost pixel of the target PU is The DC predicted value dcValBR in the region R1 is used.

  When the horizontal edge flag horEdgeFlag is 0 (vertical edge flag vertEdgeFlag is 1), the DC prediction value deriving unit 147 is adjacent to the left of the central pixel on the left side of the target PU, as shown in FIG. The pixel p [-1] [(nS-1) >> 1] is the DC predicted value dcValLT of the region R0, and the reference pixel p [-1] [nS] adjacent to the upper right of the upper right pixel of the target PU is the region R1. DC predicted value of dcValBR.

  When the horizontal edge flag is 1 and the vertical edge flag is 0, in the related art, as the DC predicted value dcValBR of the region R1, the reference pixel p [-1] [nS-1 adjacent to the left of the lower leftmost pixel of the target PU ] Is used, but the embodiment is characterized in that the reference pixel p [-1] [nS] adjacent to the lower left of the lower leftmost pixel of the target PU is used. In the case of the division pattern shown in FIG. 13B (the horizontal edge flag is 1 and the vertical edge flag is 0), a boundary (for example, a line L in FIG. 13B) that divides the region R0 and the region R1 is considered. In many cases, the reference pixel located on the dividing boundary line is accompanied by a pixel change because it is on the edge boundary, and the reference pixel located further inside from the dividing boundary is more suitable as a reference pixel used for DC prediction. It is believed that there is. Therefore, the reference pixel p [-1] [nS] located at the lower left of the lower left pixel of the target PU is more than the reference pixel p [-1] [nS-1] located at the left of the lower left pixel of the target PU. This is more suitable as a pixel used for the DC prediction value in the region R1. Therefore, compared with the prior art, the accuracy of the DC predicted value dcValBR in the region R1 is improved, and the encoding efficiency is improved.

  Similarly, when the horizontal edge flag is 0 and the vertical edge flag is 1, in the conventional technique, the reference pixel p [nS-1 adjacent to the upper right pixel of the target PU is used as the DC predicted value dcValBR of the region R1. ] [-1] is used, but the embodiment is characterized in that the reference pixel p [nS] [-1] adjacent to the upper right of the upper right pixel of the target PU is used. In the case of the division pattern shown in FIG. 13C (the horizontal edge flag is 0 and the vertical edge flag is 1), consider a boundary (for example, a line L in FIG. 13B) that divides the region R0 and the region R1. In many cases, the reference pixel located on the dividing boundary line is accompanied by a pixel change because it is on the edge boundary, and the reference pixel located further inside from the dividing boundary is more suitable as a reference pixel used for DC prediction. It is believed that there is. Therefore, the reference pixel p [nS] [-1] located at the upper right of the upper right pixel of the target PU is more than the reference pixel p [nS-1] [-1] located above the upper right pixel of the target PU. This is more suitable as a pixel used for the DC prediction value in the region R1. Therefore, the accuracy of the DC prediction value dcValBR in the region R1 is improved and the coding efficiency is improved as compared with the conventional technique.

[Comparison with conventional technology]
In the prior art, based on the vertical edge flag, the horizontal edge flag, and the pixel intensities horAbsDiff and vertAbsDiff between the reference pixels, as shown in FIGS. In each case, a reference pixel used for each region Ri (i = 0, 1) is selected for each case division, and a DC predicted value is derived.

(a) (vertEdgeFlag, horEdgeFlag) == (0,0) &&horAbsDiff> vertAbsDiff,
(b) (vertEdgeFlag, horEdgeFlag) == (0,0) && horAbsDiff <= vertAbsDiff,
(c) (vertEdgeFlag, horEdgeFlag) == (1,1),
(d) (vertEdgeFlag, horEdgeFlag) == (0,1),
(e) (vertEdgeFlag, horEdgeFlag) == (1,0),
Where horAbsDiff = Abs (p [0] [-1]-p [nS-1] [-1]), vertAbsDiff = Abs (p [-1] [0]-p [-1] [nS-1 ]). In particular, when both the horizontal edge flag and the vertical flag are 0, it is necessary to derive the pixel intensity horAbsDiff in the horizontal direction and the pixel intensity vertAbsDiff in the vertical direction from the reference pixel, and there is a problem that there are many conditional branches and the processing is complicated. is there.

  On the other hand, the DC prediction value deriving unit 147 according to the embodiment divides the division pattern of the target PU into the following three cases based on the vertical edge flag vertEdgeFlag and the horizontal edge flag horEdgeFlag. A reference pixel to be used for the region Ri (i = 0, 1) is selected, and a DC prediction value is derived.

(A) vertEdgeFlag == horEdgeFlag,
(B) (vertEdgeFlag, horEdgeFlag) == (0,1),
(C) (vertEdgeFlag, horEdgeFlag) == (1,0),
Compared with the prior art, the case division of the division pattern related to the selection of the reference pixel is reduced from 5 to 3. Also, the condition (a) (vertEdgeFlag, horEdgeFlag) == (0,0) &&horAbsDiff> vertAbsDiff, (b) (vertEdgeFlag, horEdgeFlag) == (0,0) && horAbsDiff <= vertAbsDiff, (c) (vertEdgeFlag, horEdgeFlag) == (1,1) division pattern is integrated as condition (A) vertEdgeFlag == horEdgeFlag, and the derivation of the DC prediction value of each region Ri (i = 0,1) is made common . Furthermore, in comparison with the prior art, this embodiment does not calculate the pixel intensity between the reference pixels, and the division of the divided pattern related to the selection of the reference pixel based only on the horizontal edge flag and the vertical edge flag. Can be done. That is, it is possible to perform clustering of block division patterns necessary for DC predicted value calculation only by accessing a wedgelet pattern without accessing a depth image that is a reference pixel. Further, as compared with the conventional technique, when the vertical edge flag and the horizontal edge flag are equal, there is an effect of sharing the process of deriving the DC predicted value of each region Ri (i = 0, 1). Further, in this embodiment, the reference pixels used for the derivation of the DC prediction value of each region Ri (i = 0, 1) are different reference pixels for each case division (A) to (C) of each division pattern. Furthermore, reference pixels at suitable positions are used for each divided pattern and each region. Accordingly, it is possible to derive a suitable DC prediction value for each region for each division pattern without using a reference pixel that is duplicated for each division pattern.

[Predicted image deriving unit 148]
The predicted image deriving unit 148 includes the wedgelet pattern, the derived DC predicted values dcValBR and dcValLT of each region, and the DC offset value DcOffset [i] () of each region of the target PU supplied from the DC offset information decoding unit 111. Based on i = 0..dcNumSeg-1), the prediction image predSamples [x] [y] of the target PU is derived.

  First, referring to the wedgelet pattern wedgePattern [x] [y], when the pixel position (x, y) in the target PU belongs to the region R0 (wedgePattern [x] [y] == wedgePattern [0] [0] ), When the target pixel DC predicted value predDcVal is set to dcValLT and the target pixel belongs to the region R1 (wedgePattern [x] [y]! = WedgePattern [0] [0]), the target pixel DC predicted value predDCVal is Set to dcValBR.

predDcVal = (wedgePattern [x] [y] == wedgePattern [0] [0])?
dcValLT: dcValBR (eq.7)
Next, the target pixel DC offset value dcOffset is set with reference to the DC offset value DcOffset [i] (i = 0..dcNumSeg-1).

dcOffset = DcOffset [wedgePattern [x] [y]] (eq.8)
That is, the DC offset value dcOffset [wedgePattern [x] [y]] corresponding to the value of the wedgelet pattern wedgePattern [x] [y] is set to the DC offset value dcOffset of the target pixel.

  The sum of the derived target pixel DC predicted value predDcVal and the target pixel DC offset value dcOffset is set as the predicted value of the target pixel.

predSamples [x] [y] = predDcVal + dcOffset, with x = 0..nS-1, y = 0..nS-1
As described above, the predicted image deriving unit 148 can derive the predicted image predSamples [x] [y] of the target PU.

(Action / Effect)
The DC value deriving unit 145T3 according to the embodiment divides the division pattern of the target PU into the following three cases based on the vertical edge flag vertEdgeFlag and the horizontal edge flag horEdgeFlag derived from the wedgelet pattern wedgePattern [] []. For each case classification, a reference pixel to be used for each region Ri (i = 0, 1) is selected, and a DC predicted value is derived.

(A) vertEdgeFlag == horEdgeFlag,
(B) (vertEdgeFlag, horEdgeFlag) == (0,1),
(C) (vertEdgeFlag, horEdgeFlag) == (1,0),
Compared with the prior art, the case division of the division pattern related to the selection of the reference pixel is reduced from 5 to 3. Also, the condition (a) (vertEdgeFlag, horEdgeFlag) == (0,0) &&horAbsDiff> vertAbsDiff, (b) (vertEdgeFlag, horEdgeFlag) == (0,0) && horAbsDiff <= vertAbsDiff, (c) (vertEdgeFlag, horEdgeFlag) == (1,1) division pattern is integrated as condition (A) vertEdgeFlag == horEdgeFlag, and the derivation of the DC prediction value of each region Ri (i = 0,1) is made common . Furthermore, compared to the prior art, it is possible to classify divided patterns related to selection of reference pixels based on only the horizontal edge flag and the vertical edge flag without calculating the pixel intensity between the reference pixels. It is. That is, it is possible to perform clustering of block division patterns necessary for DC predicted value calculation only by accessing a wedge pattern without accessing a depth image that is a reference pixel. Also, compared to the conventional technique, when the vertical edge flag and the horizontal edge flag are equal, the derivation process of the DC prediction value of the region Ri is shared, and the effect of reducing the processing amount related to the prediction image generation of the DMM prediction is achieved. . Further, in this embodiment, the reference pixels used for the derivation of the DC prediction value of each region Ri (i = 0, 1) are different reference pixels for each case division (A) to (C) of each division pattern. Furthermore, reference pixels at suitable positions are used for each divided pattern and each region. Accordingly, it is possible to derive a suitable DC prediction value for each region for each division pattern without using a reference pixel that is duplicated for each division pattern.

[DMM1 wedgelet pattern generator 145T2]
The DMM1 wedgelet pattern generation unit 145T2 further includes a DMM1 wedgelet pattern derivation unit 145T6, a buffer 145T5, and a wedgelet pattern list generation unit 145T4. Schematically, the DMM1 wedgelet pattern generation unit 145T2 activates the wedgelet pattern list generation unit 145T4 only at the first activation, and generates a wedgelet pattern list WedgePatternTable for each block size. Next, the generated wedgelet pattern list is stored in the buffer 145T5. Subsequently, the DMM1 wedgelet pattern deriving unit 145T6 determines the wedgelet pattern wedgePattern [x] [y] from the wedgelet pattern list WedgePatternTable stored in the buffer 145T5 based on the input target PU size nS and wedgelet pattern index wedge_full_tab_idx. ] Is derived and output to the DC predicted image deriving unit 145T1.

[Buffer 145T5]
The buffer 145T5 records the wedgelet pattern list WedgePatternTable for each block size supplied from the wedgelet pattern list generation unit 145T4.

[DMM1 wedgelet pattern deriving unit 145T6]
The DMM1 wedgelet pattern deriving unit 145T6, based on the input target PU size nS and the wedgelet pattern index wedge_full_tab_idx, from the wedgelet pattern list WedgePatternTable stored in the buffer 145T5, the wedgelet pattern wedgePattern [x ] [y] is derived and output to the DC predicted image deriving unit 145T1.

wedgePattern [x] [y] = WedgePatternTable [log2 (nS)] [wedge_full_tab_idx] [x] [y],
with x = 0..nS-1, y = 0..nS-1
Here, log2 (nS) is a logarithmic value with 2 as the target PU size.

[Wedgelet pattern list generator 145T6]
A method for generating a wedgelet pattern list in the wedgelet pattern list generation unit 145T6 will be described with reference to FIG. First, a wedgelet pattern in which all elements are 0 is generated. Next, a start point S (xs, ys) and an end point E (xe, ye) are set in the wedgelet pattern. In the example of FIG. 15A, the start point S (xs, ys) = (3, blocksize-1) and the end point E (xe, ye) = (blocksize-1,2). Next, a line segment is drawn between the start point S and the end point E using Bresenham's algorithm (shaded elements in FIG. 15B). In the example of FIG. 15C, subsequently, as shown in FIG. 15D, for example, by setting the element corresponding to the coordinates on the line segment and on the left side of the line segment to 1, the wedgelet pattern wedgePattern [x] [y] is generated. Here, blocksize is the size (vertical width, horizontal width) of the block for generating the wedgelet pattern.

  As shown in FIG. 16, the wedgelet pattern list generation unit 145T6 mainly uses each of the six start points for each wedge direction wedgeOri (wedgeOri = 0..5) based on the above-described wedgelet pattern list generation method. A wedgelet pattern corresponding to S (xs, ys) and end point E (xe, ye) is generated for each block size and added to the wedgelet pattern list WedgePatternTable.

  As described above, the wedgelet pattern list generation unit 145T6 sets (1 << log2BlkSize) × (1 << log2BlkSize) for each block size in the range up to log2BlkSize = log2 (nMinS) .. log2 (nMaxS) using log2BlkSize as a variable. ) Wedgelet pattern list WedgePatternTable.

[DMM4 wedgelet pattern generator 145T3]
The DMM4 wedgelet pattern generation unit 145T3 converts the wedgelet pattern wedgePattern [x] [y] indicating the division pattern of the target PU into the decoded pixel value recTexPic of the luminance on the viewpoint image TexturePic corresponding to the target PU on the depth map DepthPic. Based on this, it outputs to the DC prediction image deriving unit 145T1. Schematically, the DMM4 wedgelet pattern generation unit binarizes the two blocks R0 and R1 of the target PU on the depth map by the average value of the luminance of the target block on the corresponding viewpoint image TexturePic. To derive.

  First, the DMM4 wedgelet pattern generation unit 145T3 reads, from the external frame memory 16, the luminance decoded pixel value recTextPic of the corresponding block on the viewpoint image TexturePic corresponding to the target PU from the external frame memory 16, and the reference pixel refSamples [x ] Set to [y] by the following formula.

refSamples [x] [y] = recTexPic [xB + x] [yB + y], with x = 0..nS-1, y = 0..nS-1
Based on the reference pixel refSamples [x] [y], the sum SumVals of the pixel values of the corresponding block is derived by the following equation.

sumRefVals = ΣrefSamples [x] [y], with x = 0..nS-1, y = 0..nS-1
Next, the threshold value threshVals is derived by the following equation based on the sum sumRefVals and the target PU size nS. That is, the average pixel value of the corresponding block is derived.

threshVal = (sumRefVals >> (2 * log2 (nS))
Here, instead of the above formula, a value obtained by dividing the sum sumRefVals by the square number nS * nS of the target PU size nS may be used as the threshold threshVal.

  Subsequently, the DMM4 wedgelet pattern generation unit 145T3 refers to the derived threshold value threshVal and the reference pixel refSamples [x] [y], and determines the wedgelet pattern wedgePattern [x] [y] indicating the division pattern of the target PU. Derived by the following formula and output.

wedgePattern [x] [y] = (refSamples [x] [y]> threshVal)
That is, when the reference pixel refSamples [x] [y] is larger than the threshold value threshVal, 1 is set to the element (x, y) of the wedge pattern. When the reference pixel refSamples [x] [y] is equal to or less than the threshold value threshVal, 0 is set to the element (x, y) of the wedgelet pattern.

(Action / Effect)
When the DMM prediction is executed, the predicted image generation unit included in the video decoding device 1 according to the present embodiment described above, based on the vertical edge flag vertEdgeFlag and the horizontal edge flag horEdgeFlag derived from the wedgelet pattern, The division pattern of the target PU is divided into the following three cases, and for each case division, a reference pixel used for each region Ri (i = 0, 1) is selected, and a DC prediction value is derived.

(A) vertEdgeFlag == horEdgeFlag,
(B) (vertEdgeFlag, horEdgeFlag) == (0,1),
(C) (vertEdgeFlag, horEdgeFlag) == (1,0),
Compared with the prior art, the case of the division pattern related to the selection of the reference pixel is reduced from 5 to 3, and the condition in the prior art (a) (vertEdgeFlag, horEdgeFlag) == (0,0) &&horAbsDiff> vertAbsDiff , (b) (vertEdgeFlag, horEdgeFlag) == (0,0) && horAbsDiff <= vertAbsDiff, (c) (vertEdgeFlag, horEdgeFlag) == The division pattern of (1,1) is the condition (A) vertEdgeFlag == horEdgeFlag And derivation of the DC prediction value of each region Ri (i = 0, 1) is made common. Therefore, compared with the conventional technique, it is possible to classify the divided pattern related to the selection of the reference pixel based only on the horizontal edge flag and the vertical edge flag without calculating the pixel intensity between the reference pixels. It is. In addition, the conditional branch is reduced from 5 to 3, and the branch processing is reduced. Compared to the prior art, when the vertical edge flag and the horizontal edge flag are the same, the derivation process of the DC prediction value of each region Ri is made common, so that the prediction image can be generated while maintaining the coding efficiency. There exists an effect which reduces the processing amount which concerns. Further, in this embodiment, the reference pixels used for the derivation of the DC prediction value of each region Ri (i = 0, 1) are different reference pixels for each case division (A) to (C) of each division pattern. Furthermore, reference pixels at suitable positions are used for each divided pattern and each region. Accordingly, it is possible to derive a suitable DC prediction value for each region for each division pattern without using a reference pixel that is duplicated for each division pattern.

[Moving picture encoding device]
Hereinafter, the moving picture encoding apparatus 2 according to the present embodiment will be described with reference to FIG.

(Outline of video encoding device)
Generally speaking, the moving image encoding device 2 is a device that generates and outputs encoded data # 1 by encoding the input image # 10. Here, the input image # 10 is a layer image including one or a plurality of viewpoint images TexturePic and a depth map DepthPic at the same time corresponding to the viewpoint image TexturePic.

(Configuration of video encoding device)
First, a configuration example of the video encoding device 2 will be described with reference to FIG. FIG. 17 is a functional block diagram showing the configuration of the moving image encoding device 2. As illustrated in FIG. 17, the moving image encoding apparatus 2 includes an encoding setting unit 21, an inverse quantization / inverse conversion unit 22, a predicted image generation unit 23, an adder 24, a frame memory 25, a subtractor 26, a conversion / A quantization unit 27 and an encoded data generation unit 29 are provided.

  The encoding setting unit 21 generates image data related to encoding and various setting information based on the input image # 10.

  Specifically, the encoding setting unit 21 generates the next image data and setting information.

  First, the encoding setting unit 21 generates the CU image # 100 for the target CU by sequentially dividing the input image # 10 into slice units, tree block units, and CU units.

  Also, the encoding setting unit 21 generates header information H ′ based on the result of the division process. The header information H ′ includes (1) information on the size and shape of the tree block belonging to the target slice and the position in the target slice, and (2) the size, shape and shape of the CU belonging to each tree block. CU information CU ′ for the position at

  Further, the encoding setting unit 21 refers to the CU image # 100 and the CU information CU 'to generate PT setting information PTI'. The PT setting information PTI 'includes information on all combinations of (1) possible division patterns of the target CU for each PU and (2) prediction modes that can be assigned to each PU.

  The encoding setting unit 21 supplies the CU image # 100 to the subtractor 26. In addition, the encoding setting unit 21 supplies the header information H ′ to the encoded data generation unit 29. Also, the encoding setting unit 21 supplies the PT setting information PTI ′ to the predicted image generation unit 23.

  The inverse quantization / inverse transform unit 22 performs inverse quantization and inverse orthogonal transform on the quantized prediction residual for each block supplied from the transform / quantization unit 27, thereby predicting the prediction residual for each block. To restore. The inverse orthogonal transform has already been described with respect to the inverse quantization / inverse transform unit 13 shown in FIG. 3, and thus the description thereof is omitted here.

  Further, the inverse quantization / inverse transform unit 22 integrates the prediction residual for each block according to the division pattern specified by the TT division information (described later), and generates a prediction residual D for the target CU. The inverse quantization / inverse transform unit 22 supplies the prediction residual D for the generated target CU to the adder 24.

  The predicted image generation unit 23 refers to the locally decoded image P ′ and the PT setting information PTI ′ recorded in the frame memory 25 to generate a predicted image Pred for the target CU. The predicted image generation unit 23 sets the prediction parameter obtained by the predicted image generation process in the PT setting information PTI ′, and transfers the set PT setting information PTI ′ to the encoded data generation unit 29. Note that the predicted image generation process performed by the predicted image generation unit 23 is the same as that performed by the predicted image generation unit 14 included in the video decoding device 1, and thus description thereof is omitted here.

  The adder 24 adds the predicted image Pred supplied from the predicted image generation unit 23 and the prediction residual D supplied from the inverse quantization / inverse transform unit 22 to thereby obtain the decoded image P for the target CU. Generate.

  Decoded decoded images P are sequentially recorded in the frame memory 25. In the frame memory 25, decoded images corresponding to all tree blocks decoded prior to the target tree block (for example, all tree blocks preceding in the raster scan order) at the time of decoding the target tree block. It is recorded.

  The subtractor 26 generates a prediction residual D for the target CU by subtracting the prediction image Pred from the CU image # 100. The subtractor 26 supplies the generated prediction residual D to the transform / quantization unit 27.

  The transform / quantization unit 27 generates a quantized prediction residual by performing orthogonal transform and quantization on the prediction residual D. Here, the orthogonal transformation refers to transformation from the pixel region to the frequency region. Examples of inverse orthogonal transform include DCT transform (Discrete Cosine Transform), DST transform (Discrete Sine Transform), and the like.

  Specifically, the transform / quantization unit 27 refers to the CU image # 100 and the CU information CU ', and determines a division pattern of the target CU into one or a plurality of blocks. Further, according to the determined division pattern, the prediction residual D is divided into prediction residuals for each block.

  The transform / quantization unit 27 generates a prediction residual in the frequency domain by orthogonally transforming the prediction residual for each block, and then quantizes the prediction residual in the frequency domain to Generate quantized prediction residuals. Note that when the SDC flag is 1, the transform unit / quantization unit 27 omits frequency transform / quantization, and sets the prediction residual D (or resSamples [x] [y]) for each pixel of the target TU to 0. To do.

  In addition, the transform / quantization unit 27 generates the quantization prediction residual for each block, TT division information that specifies the division pattern of the target CU, information about all possible division patterns for each block of the target CU, and TT setting information TTI ′ including is generated. The transform / quantization unit 27 supplies the generated TT setting information TTI ′ to the inverse quantization / inverse transform unit 22 and the encoded data generation unit 29.

  The encoded data generation unit 29 encodes header information H ′, TT setting information TTI ′, and PT setting information PTI ′, and multiplexes the encoded header information H, TT setting information TTI, and PT setting information PTI. Coded data # 1 is generated and output.

(Action / Effect)
When the DMM prediction is executed, the predicted image generation unit included in the video encoding device 2 according to the present embodiment described above is based on the vertical edge flag vertEdgeFlag and the horizontal edge flag horEdgeFlag that are derived from the wedgelet pattern. The division pattern of the target PU is divided into the following three cases, and for each case division, a reference pixel used for each region Ri (i = 0, 1) is selected, and a DC prediction value is derived.

(A) vertEdgeFlag == horEdgeFlag,
(B) (vertEdgeFlag, horEdgeFlag) == (0,1),
(C) (vertEdgeFlag, horEdgeFlag) == (1,0),
Compared with the prior art, the case of the division pattern related to the selection of the reference pixel is reduced from 5 to 3, and the condition in the prior art (a) (vertEdgeFlag, horEdgeFlag) == (0,0) &&horAbsDiff> vertAbsDiff , (b) (vertEdgeFlag, horEdgeFlag) == (0,0) && horAbsDiff <= vertAbsDiff, (c) (vertEdgeFlag, horEdgeFlag) == The division pattern of (1,1) is the condition (A) vertEdgeFlag == horEdgeFlag And derivation of the DC prediction value of each region Ri (i = 0, 1) is made common. Therefore, compared with the conventional technique, it is possible to classify the divided pattern related to the selection of the reference pixel based only on the horizontal edge flag and the vertical edge flag without calculating the pixel intensity between the reference pixels. It is. In addition, the conditional branch is reduced from 5 to 3, and the branch processing is reduced. Compared to the prior art, when the vertical edge flag and the horizontal edge flag are the same, the derivation process of the DC prediction value of each region Ri is made common, so that the prediction image can be generated while maintaining the coding efficiency. There exists an effect which reduces the processing amount which concerns. Further, in this embodiment, the reference pixels used for the derivation of the DC prediction value of each region Ri (i = 0, 1) are different reference pixels for each case division (A) to (C) of each division pattern. Furthermore, reference pixels at suitable positions are used for each divided pattern and each region. Accordingly, it is possible to derive a suitable DC prediction value for each region for each division pattern without using a reference pixel that is duplicated for each division pattern.

[Application example]
The above-described moving image encoding device 2 and moving image decoding device 1 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 may be an artificial moving image (including CG and GUI) generated by a computer or the like.

  First, it will be described with reference to FIG. 18 that the above-described moving image encoding device 2 and moving image decoding device 1 can be used for transmission and reception of moving images.

  FIG. 18A is a block diagram illustrating a configuration of a transmission device PROD_A in which the moving image encoding device 2 is mounted. As illustrated in (a) of FIG. 18, the transmission device PROD_A modulates a carrier wave with an encoding unit PROD_A1 that obtains encoded data by encoding a moving image and 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 moving image encoding apparatus 2 described above is used as the encoding unit PROD_A1.

  The transmission device PROD_A is a camera PROD_A4 that captures a moving image, a recording medium PROD_A5 that records the moving image, and an input terminal PROD_A6 for inputting the moving image from the outside as a supply source of the moving image input to the encoding unit PROD_A1. And an image processing unit A7 for generating or processing an image. FIG. 18A illustrates a configuration in which the transmission apparatus PROD_A includes all of these, but a part of the configuration may be omitted.

  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 according to the recording encoding method may be interposed between the recording medium PROD_A5 and the encoding unit PROD_A1.

  FIG. 18B is a block diagram illustrating a configuration of the receiving device PROD_B in which the video decoding device 1 is mounted. As illustrated in FIG. 18B, 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 moving picture decoding apparatus 1 described above is used as the decoding unit PROD_B3.

  The receiving device PROD_B has a display PROD_B4 for displaying a moving image, a recording medium PROD_B5 for recording the moving image, and an output terminal for outputting the moving image to the outside as a supply destination of the moving image output by the decoding unit PROD_B3. PROD_B6 may be further provided. FIG. 18B illustrates a configuration in which the reception apparatus PROD_B includes all of these, but a part may be omitted.

  The recording medium PROD_B5 may be used for recording a non-encoded moving image, or may be 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. Further, 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 or the like) / client (television receiver, personal computer, smartphone, etc.) such as a VOD (Video On Demand) service or a video sharing service using the Internet transmits and receives a modulated signal by communication. This is an example of PROD_A / reception device PROD_B (usually, 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, it will be described with reference to FIG. 19 that the above-described moving image encoding device 2 and moving image decoding device 1 can be used for recording and reproduction of moving images.

  FIG. 19A is a block diagram showing a configuration of a recording apparatus PROD_C in which the above-described moving picture encoding apparatus 2 is mounted. As shown in FIG. 19A, the recording apparatus PROD_C has 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 moving image encoding apparatus 2 described above is used as the encoding unit PROD_C1.

  The recording medium PROD_M may be of a type built in the recording device PROD_C, such as (1) HDD (Hard Disk Drive) or SSD (Solid State Drive), or (2) SD memory. It may be 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 (registered) Or a drive device (not shown) built in the recording device PROD_C.

  The recording device PROD_C receives a moving image as a supply source of a moving image to be input to the encoding unit PROD_C1, a camera PROD_C3 that captures a moving image, an input terminal PROD_C4 for inputting a moving image from the outside, and a moving image. May include a receiving unit PROD_C5 and an image processing unit C6 that generates or processes an image. FIG. 19A illustrates a configuration in which the recording apparatus PROD_C includes all of these, but a part of the configuration 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, and an HD (Hard Disk) recorder (in this case, the input terminal PROD_C4 or the receiving unit PROD_C5 is a main supply source of moving images). In addition, a camcorder (in this case, the camera PROD_C3 is a main source of moving images), a personal computer (in this case, the receiving unit PROD_C5 is a main source of moving images), a smartphone (in this case, the camera PROD_C3 or The receiving unit PROD_C5 or the image processing unit C6 is a main supply source of moving images) is also an example of such a recording apparatus PROD_C.

  FIG. 19B is a block diagram illustrating a configuration of a playback device PROD_D in which the above-described video decoding device 1 is mounted. As shown in (b) of FIG. 19, 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 coded data read by the read unit PROD_D1. And a decoding unit PROD_D2 to be obtained. The moving picture decoding apparatus 1 described above is used as the decoding unit PROD_D2.

  Note that 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 a 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 DVD or BD. Good.

  In addition, the playback device PROD_D has a display PROD_D3 that displays a moving image, an output terminal PROD_D4 that outputs the moving image to the outside, and a transmission unit that transmits the moving image as a supply destination of the moving image output by the decoding unit PROD_D2. PROD_D5 may be further provided. FIG. 19B illustrates a configuration in which the playback apparatus PROD_D includes all of these, but some of the configurations may be omitted.

  The transmission unit PROD_D5 may transmit an unencoded moving image, or transmits encoded data encoded by a transmission encoding method different from the recording encoding method. You may do. In the latter case, it is preferable to interpose an encoding unit (not shown) that encodes a moving image with an encoding method for transmission 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 supply destination of moving images). . 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, the output terminal PROD_D4 or the transmission unit PROD_D5 is the main video image supply destination), laptop or tablet PC (in this case, the display PROD_D3 or the transmission unit PROD_D5 is a moving image) 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 moving picture decoding apparatus 1 and the moving picture encoding apparatus 2 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) may be implemented in software.

  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. An object of the present invention is to provide a recording medium in which a program code (execution format program, intermediate code program, source program) of a control program for each of the above devices, which is software that realizes the above-described functions, is recorded so as to be readable by a computer. This can also be achieved by supplying 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 tapes such as magnetic tape and cassette tape, 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 (Blu-ray Disc (registered trademark)) and other optical disks, 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) / semiconductor memories such as flash ROM, or PLD (Programmable Logic Device) Logic circuits such as an FPGA (Field Programmable Gate Array) can be used.

  Further, each of the above devices may be configured to be connectable to a communication network, and the 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, 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 such as IrDA (Infrared Data Association) or remote control even with wired such as IEEE (Institute of Electrical and Electronic Engineers) 1394, USB, power line carrier, cable TV line, telephone line, ADSL (Asymmetric Digital Subscriber Line) line, etc. , Bluetooth (registered trademark), IEEE 802.11 wireless, HDR (High Data Rate), NFC (Near Field Communication), DLNA (Digital Living Network Alliance), mobile phone network, satellite line, terrestrial digital network, etc. Is possible. 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 present invention can be suitably applied to an image decoding apparatus that decodes encoded data obtained by encoding image data and an image encoding apparatus that generates encoded data obtained by encoding image data. 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.

1 video decoding device (image decoding device)
11 Variable length decoding unit (DMM prediction mode information decoding means)
111 DC offset information decoding unit (DC offset information decoding means)
13 Inverse quantization / inverse transform unit 14 Predicted image generation unit 141 Prediction unit setting unit 142 Reference pixel setting unit 143 Switch 144 Reference pixel filter unit 145 Predicted image derivation unit 145D DC prediction unit 145P Planar prediction unit 145A Angular prediction unit 145T DMM prediction (DMM prediction device)
145T1 DC predicted image derivation unit 145T2 DMM1 wedgelet pattern generation unit 145T3 DMM4 wedgelet pattern generation unit 145T5 wedgelet pattern list generation unit 145T5 buffer 145T6 DMM1 wedgelet pattern derivation unit 146 edge flag derivation unit 147 DC prediction value derivation unit 148 prediction image Deriving unit 15 Adder 16 Frame memory 2 Video encoding device 21 Encoding setting unit 22 Inverse quantization / inverse conversion unit 23 Predictive image generation unit 24 Adder 25 Frame memory 26 Subtractor 27 Conversion / quantization unit 29 Encoding Data generation unit (DMM prediction mode information encoding means)

Claims (10)

Wedgelet pattern deriving means for deriving a wedgelet pattern indicating that the target PU is divided into the first region and the second region;
Edge flag deriving means for deriving a vertical edge flag and a horizontal edge flag from the wedgelet pattern;
DC predicted value derivation means for deriving the DC predicted value of each region from the reference pixel of the target PU;
A DMM prediction apparatus comprising prediction image derivation means for deriving a prediction image of a target PU based on the wedgelet pattern, a DC prediction value of each region, and DC offset information of each region,
The DC prediction value deriving means includes the case where the vertical edge flag is equal to the horizontal edge flag, the case where the vertical edge flag is 0 and the horizontal edge flag is 1, and the case where the vertical edge flag is 1 and the horizontal edge flag. A DMM prediction apparatus, wherein reference pixels used for derivation of a DC prediction value of each region are different from each other in the case where is 0. When the vertical edge flag and the horizontal edge flag are the same, the DC prediction value deriving means uses a reference pixel at a position of −1 in the x direction and 0 in the y direction on the basis of the upper left pixel of the target PU. , The average value of the reference pixel at the position of 0 in the x direction and −1 in the y direction is the DC predicted value for the first region,
A reference pixel at a position of 2 * nS-1 in the x direction and 2 * nS-1 in the x direction and a position of -1 in the y direction with respect to the upper left pixel of the target PU 2. The DMM prediction apparatus according to claim 1, wherein an average value with reference pixels in the second region is derived as a DC prediction value for the second region.   When the vertical edge flag is 0 and the horizontal edge flag is 1, the DC prediction value deriving unit sets a reference pixel adjacent to the center pixel on the upper side of the target PU as a DC prediction value for the first region. The DMM prediction apparatus according to claim 1, wherein a reference pixel adjacent to the lower left of the lower left pixel of the target PU is derived as a DC prediction value for the second region.   When the vertical edge flag is 1 and the horizontal edge flag is 0, the DC prediction value deriving unit sets a reference pixel adjacent to the left of the central pixel on the left side of the target PU as a DC prediction value for the first region. The DMM prediction apparatus according to claim 1, wherein a reference pixel adjacent to the upper right of the upper right pixel of the target PU is derived as a DC prediction value for the second region.   The first area is an area composed of a pixel having a value of a wedgelet pattern equal to a value of a wedgelet pattern of the uppermost left pixel of the target PU and the uppermost left pixel. 4. The DMM prediction apparatus according to 4.   6. The DMM prediction apparatus according to claim 5, wherein the second region is a region including pixels having a wedgelet pattern value different from a wedgelet pattern value of an upper left pixel of the target PU.   The edge flag deriving means sets 1 as the vertical edge flag when the value of the wedge pattern of the upper leftmost pixel of the target PU and the value of the wedgelet pattern of the uppermost right pixel of the target PU are different from each other. 7. The DMM prediction apparatus according to claim 6, wherein when the value of the wedge pattern of the upper left pixel is equal to the value of the wedge let pattern of the upper right pixel, 0 is set in the vertical edge flag.   The edge flag deriving means sets the horizontal flag to 1 when the value of the wedge pattern of the upper left pixel of the target PU is different from the value of the wedge let pattern of the lower left pixel of the target PU, and sets the upper left 8. The DMM prediction apparatus according to claim 7, wherein when the value of the wedge pattern of the pixel is equal to the value of the wedgelet pattern of the upper rightmost pixel, 0 is set in the horizontal edge flag. The DMM prediction apparatus according to any one of claims 1 to 8,
An image decoding apparatus comprising DMM prediction mode information decoding means for decoding DMM prediction mode information related to DMM prediction,
The DMM prediction apparatus performs DMM prediction when the DMM prediction mode information indicates DMM prediction. The DMM prediction apparatus according to any one of claims 1 to 8,
An image encoding device including DMM prediction mode information encoding means for encoding DMM prediction mode information related to DMM prediction,
The DMM prediction apparatus performs DMM prediction when the DMM prediction mode information indicates DMM prediction.

Images