JP2015035641A - Image decoder and image encoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanism that controls whether inter-layer image prediction in which pixels outside a reference layer corresponding region are referred to can be applied to a hierarchical encoding system.SOLUTION: An image decoder which decodes hierarchical encoded data includes: reference layer corresponding region information decoding means of decoding reference layer corresponding region information showing corresponding regions of an object layer and a reference layer; inter-layer image prediction restriction flag decoding means of decoding an inter-layer image prediction restriction flag inhibiting inter-layer image prediction meeting a predetermined condition; re-sampling means of generating a re-sample reference layer picture based upon a reference layer picture having been decoded and the reference layer corresponding region information; and prediction image generation means of generating prediction images in respective prediction units constituting the picture of the object layer. The prediction image generation means generates a prediction image as a prediction unit through inter-layer image prediction which does not meet the predetermined condition when the inter-layer image prediction restriction flag is true and a prediction system for the prediction unit is inter-layer image prediction.

Description

  The present invention relates to an image decoding apparatus that decodes hierarchically encoded data in which an image is hierarchically encoded, and an image encoding apparatus that generates hierarchically encoded data by hierarchically encoding an image.

  One of information transmitted in the communication system or information recorded in the storage device is an image or a moving image. 2. Description of the Related Art Conventionally, a technique for encoding an image for transmitting and storing these images (hereinafter including moving images) is known.

  As a moving picture coding system, AVC (H.264 / MPEG-4 Advanced Video Coding) and its successor codec HEVC (High-Efficiency Video Coding) are known (Non-patent Document 1).

  In these moving image encoding methods, a predicted image is usually generated based on a local decoded image obtained by encoding / decoding an input image, and obtained by subtracting the predicted image from the input image (original image). Prediction residuals (sometimes referred to as “difference images” or “residual images”) are encoded. In addition, examples of the method for generating a predicted image include inter-screen prediction (inter prediction) and intra-screen prediction (intra prediction).

  In intra prediction, predicted images in a picture are sequentially generated based on a locally decoded image in the same picture.

  In inter prediction, a predicted image is generated by motion compensation between pictures. A decoded picture used for predictive image generation in inter prediction is called a reference picture.

  In recent years, a hierarchical encoding technique for hierarchically encoding an image according to a necessary data rate has been proposed. SHVC (Scalable HEVC) is known as one of representative hierarchical coding methods (Non-patent Document 2).

  SHVC supports spatial scalability, temporal scalability, and SNR scalability. For example, in the case of spatial scalability, an image downsampled from an original image to a desired resolution is encoded as a lower layer. Next, the upper layer performs inter-layer prediction in order to remove redundancy between layers.

  Inter-layer prediction includes inter-layer image prediction and inter-layer motion prediction. In inter-layer image prediction, a predicted image is generated using a decoded image of a lower layer. In inter-layer motion prediction, motion information prediction values are derived using motion information of lower layers.

  In SHVC, any one of inter prediction, intra prediction, and inter-layer image prediction can be used to generate a predicted image.

  The decoded image rlPicSample of the lower layer picture (reference layer picture rlPic) used in SHVC inter-layer image prediction is applied after resampling (also called scaling processing) is applied to the size of the upper layer (target layer) picture. The resample reference layer picture rsPic (inter-layer reference picture) is recorded in the decoded picture buffer as an image rsPicSample. In SHVC, a mechanism for recording and managing a decoded picture in the DPB is applied to the decoded picture of the target layer, as in HEVC.

  Also, the motion information rlPicMotion of the reference layer picture rlPic used in the inter-layer motion prediction of SHVC is applied to the resampling reference layer picture rsPic (interlayer reference picture) after applying the resampling process to the picture size of the target layer. It is recorded in the reference picture memory as motion information rsPicMotion. Note that the resample processing of motion information is also called inter-layer motion mapping (MFM: Motion Field Mapping), and the image resample processing is also called inter-layer image mapping.

  Further, in SHVC, in order to generate a resample image rsPicSample of the resample reference layer picture rsPic and resample motion information rsPicMotion from the reference layer picture rlPic, the resample reference layer picture rsPic (or the target picture curPic) Reference layer corresponding region information indicating which region corresponds to the reference layer picture rlPic is used. For example, when generating the resampled image rsPicSample of the resample reference layer picture rsPic, the pixels outside the reference layer corresponding area on the resample reference layer picture rsPic are closest to the reference layer corresponding to the resample reference layer picture rsPic. It is generated by padding with pixels on the region boundary. Alternatively, the coordinates (xP, yP) of the pixels outside the reference layer corresponding area are replaced with the coordinates (xP ', yP') of the boundary pixels in the closest reference layer corresponding area, and the coordinates (xP ', yP) of the boundary pixels are replaced. It is generated by deriving the position (xRL, yRL) of the reference pixel of the reference layer picture rlPic corresponding to ') and applying the resample filter around the position of the reference pixel.

"Recommendation H.265 (04/13)", ITU-T (released June 7, 2013) JCTVC-M1008_v3 `` SHVC Working Draft 2 '', Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11 13th Meeting: Incheon, KR, 18- 26 Apr. 2013 (released on June 14, 2013)

  In the SHVC cited as the prior art, when a prediction image of a certain prediction unit PU on the target picture curPic is generated by inter-layer image prediction, an image outside the reference layer corresponding region on the resample reference layer picture rsPic is referred to Can do. That is, the prediction image of the inter-layer image prediction can include pixels generated by padding on the resample reference layer picture rsPic. However, in the inter-layer image prediction, a prediction image including pixels generated by padding has a low prediction accuracy, and thus there is a problem in that the encoding efficiency decreases and the image quality decreases. Also, in the prior art, when generating a resample pixel with coordinates outside the reference layer corresponding area on the resample reference layer picture rsPic, the coordinates are replaced with the boundary pixels of the closest reference layer corresponding area. There has been a problem that the process of generating sample pixels 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 mechanism for controlling applicability of inter-layer image prediction that refers to pixels outside the reference layer corresponding region in the hierarchical coding scheme. There is to do. It is also intended to realize an image encoding device and an image decoding device that encode / decode encoded data with a smaller code amount, processing amount, and memory amount.

In order to solve the above problems, an image decoding apparatus according to the present invention decodes hierarchically encoded data in which image information relating to images of different quality for each layer is hierarchically encoded, and is a target to be decoded. An image decoding device for restoring an image in a layer,
Reference layer corresponding region information decoding means for decoding reference layer corresponding region information indicating a corresponding region between the target layer and the reference layer;
Re-sampling means for generating a re-sampled reference layer picture by associating the image and motion information of the reference layer picture with the picture of the target layer based on the decoded reference layer picture and the reference layer corresponding region information;
Prediction image generation means for generating a prediction image of each prediction unit constituting the picture of the target layer,
The resampling means further includes reference pixel position deriving means for deriving a reference pixel position of a reference layer picture corresponding to each pixel of the resampled reference layer picture,
Resampled image generation means for generating each pixel of the resample reference layer picture using a predetermined resample filter on a pixel on a filter region including the derived reference pixel position;
The resampling image generation means, when the filter region includes coordinates outside the screen of the reference layer picture, replaces the coordinates with the screen edge closest to the reference layer picture.

  As described above, according to the above configuration, when the coordinates (xP, yP) on the resample reference layer picture are outside the reference layer corresponding region, the reference pixel position (xRef, yRef) on the reference layer picture is directly derived. . Therefore, the derivation process related to the derivation of the reference pixel position can be simplified as compared with the conventional technique. Further, according to the above configuration, when generating a resample pixel of each coordinate outside the reference layer corresponding area on the resample reference layer picture, the filter area on the reference layer picture to which the resample filter is applied is out of the screen. If there is a pixel with the coordinate of, a resampled image is generated using a pixel having a high correlation with the pixel (close spatial distance). As a result, the accuracy of the resampled image outside the reference layer corresponding region can be improved as compared with the conventional technique. Moreover, regarding the inter-layer image prediction that refers to the pixels outside the reference layer corresponding region, the prediction accuracy can be improved as compared with the conventional technique. Therefore, the encoding efficiency is also improved. In particular, in the present invention, it is possible to generate an area in which the pixel value of the resampled image changes smoothly in an area having a width ΔFX and a height ΔFY in the horizontal direction outside the boundary of the reference layer corresponding area. Therefore, in inter-layer image prediction, the prediction accuracy of inter-layer image prediction that refers to the region of width ΔFX and height ΔFY in the horizontal direction outside the reference layer corresponding region outside the reference layer corresponding region is improved. Can be made.

In order to solve the above problems, an image decoding apparatus according to the present invention decodes hierarchically encoded data in which image information relating to images of different quality for each layer is hierarchically encoded, and is a target to be decoded. An image decoding device for restoring an image in a layer,
Reference layer corresponding region information decoding means for decoding reference layer corresponding region information indicating a corresponding region between the target layer and the reference layer;
Re-sampling means for generating a re-sampled reference layer picture by associating the image and motion information of the reference layer picture with the picture of the target layer based on the decoded reference layer picture and the reference layer corresponding region information;
A prediction image generating unit that generates a prediction image of each prediction unit constituting the picture of the target layer,
The prediction image generation unit generates the prediction image of the prediction unit by inter-layer image prediction that does not satisfy a predetermined condition when the prediction method of the prediction unit is inter-layer image prediction.

  As described above, according to the above configuration, based on the decoded reference layer picture and the reference layer corresponding region information, the image and motion information of the reference layer picture are associated with the picture of the target layer, and the resampled reference layer picture Since the image and the motion information are generated, the accuracy of the inter-layer image prediction and the inter-layer motion prediction can be improved. As a result, the code efficiency can be further improved. Moreover, according to the said structure, since use of the image prediction between layers satisfy | filling the predetermined conditions with low prediction accuracy is prohibited, encoding efficiency can be improved.

Furthermore, in the image decoding apparatus according to the present invention,
An inter-layer image prediction constraint flag decoding unit that decodes an inter-layer image prediction constraint flag that prohibits inter-layer image prediction satisfying a predetermined condition;
When the inter-layer image prediction constraint flag is true and the prediction method of the prediction unit is inter-layer image prediction, the predicted image generation means performs prediction of the prediction unit by inter-layer image prediction that does not satisfy the predetermined condition. A prediction image is generated.

  According to the above configuration, it is possible to control whether or not inter-layer image prediction that satisfies a predetermined condition is prohibited. In particular, when the inter-layer image prediction constraint flag is true, the use of inter-layer image prediction that satisfies a predetermined condition with low prediction accuracy is prohibited, so that the encoding efficiency can be improved.

  Furthermore, in the image decoding apparatus according to the present invention, the inter-layer image prediction satisfying the predetermined condition is a correspondence region on the resample reference layer picture corresponding to the prediction unit and the reference layer correspondence in the inter-layer image prediction. (1) The left end coordinate of the corresponding region is smaller than the left end coordinate of the reference layer corresponding region, (2) the right end coordinate of the corresponding region is larger than the right end coordinate of the reference layer corresponding region, and (3) the corresponding The upper end coordinate of the region is smaller than the upper end coordinate of the reference layer corresponding region, and (4) the lower end coordinate of the corresponding region is larger than the lower end coordinate of the reference layer corresponding region. Features.

  As described above, according to the above configuration, use of inter-layer image prediction that refers to an image outside the reference layer corresponding region can be prohibited. Therefore, since inter-layer image prediction that refers to pixels outside the reference layer corresponding region with low prediction accuracy is not used, an image decoding device with higher encoding efficiency can be realized. Further, according to the above configuration, when the inter-layer image prediction constraint flag is decoded, if the flag is true, an image outside the reference layer corresponding region on the resample reference layer picture (reference layer) in the target sequence. Since it is understood that “outside corresponding region” is not referred to when inter-layer image prediction is performed, generation of an image outside the reference layer corresponding region can be omitted when generating a resampled image of the resampled reference layer picture.

  Furthermore, in the image decoding apparatus according to the present invention, the inter-layer image prediction satisfying the predetermined condition is a correspondence region on the resample reference layer picture corresponding to the prediction unit and the reference layer correspondence in the inter-layer image prediction. (1) The right end coordinate of the corresponding region is smaller than the left end coordinate of the reference layer corresponding region, (2) The left end coordinate of the corresponding region is larger than the right end coordinate of the reference layer corresponding region, and (3) the corresponding The lower end coordinate of the region is smaller than the upper end coordinate of the reference layer corresponding region, and (4) the upper end coordinate of the corresponding region is larger than the lower end coordinate of the reference layer corresponding region. Features.

  As described above, according to the above configuration, it is possible to prohibit the use of inter-layer image prediction that refers only to images outside the reference layer corresponding region. Therefore, since inter-layer image prediction that refers only to pixels outside the reference layer corresponding region with low prediction accuracy is not used, an image decoding device with higher encoding efficiency can be realized.

  Furthermore, in the image decoding device according to the present invention, when the inter-layer image prediction constraint flag is true, the re-sampling unit only selects an image in the reference layer corresponding region among the images of the re-sample reference layer picture. Is generated.

  As described above, according to the above configuration, when the inter-layer image prediction constraint flag is decoded, if the flag is true, an image (reference layer) outside the reference layer corresponding region on the resample reference layer picture in the target sequence. Since it is understood that “outside corresponding region” is not referred to during inter-layer image prediction, generation of an image outside the reference layer corresponding region can be omitted when generating a resampled image of the resampled reference layer picture. Therefore, it is possible to simplify the resampling process and reduce the memory required for holding an image outside the reference layer corresponding area.

  Furthermore, in the image decoding apparatus according to the present invention, the inter-layer image prediction constraint flag decoding means decodes the inter-layer image prediction constraint flag based on the presence / absence of reference layer corresponding region information.

  As described above, according to the above configuration, the inter-layer image prediction constraint flag is explicitly decoded only when there is reference layer correspondence information. That is, when there is no reference layer corresponding region information, decoding of the inter-layer image prediction constraint flag is omitted. Therefore, it is possible to reduce processing related to decoding of the inter-layer image prediction constraint flag and further reduce the amount of codes.

  Furthermore, in the image decoding apparatus according to the present invention, the reference layer corresponding region information decoding means decodes reference layer corresponding region information common to the entire target sequence in units of sequences, and reference layer corresponding region information corresponding to each picture. Is decoded in units of pictures.

  As described above, according to the above configuration, based on the inter-layer correspondence parameter between the target layer (for example, the enhancement layer) and the reference layer (for example, the base layer) derived based on the reference layer corresponding region, The target pixel can be generated by determining the position of the reference pixel on the reference layer picture corresponding to each pixel on the sample reference layer picture and applying a predetermined resample filter to the reference pixel and surrounding pixels . Thereby, the effect which improves the precision of the resample image used by the image prediction between layers can be acquired. In particular, for a sequence in which the corresponding region of the target layer and the reference layer changes in units of pictures, compared to the case of performing inter-layer image mapping based on the inter-layer correspondence parameter derived from the reference layer corresponding region information, By performing the inter-layer image mapping based on the inter-layer correspondence parameter derived from the reference layer correspondence area information in units of pictures, there is an effect of further improving the accuracy of the resampled image used in the inter-layer image prediction. . As a result, the prediction accuracy of inter-layer image prediction is also improved, so that the encoding efficiency can be improved.

  Further, according to the above configuration, the inter-layer correspondence parameters (OffsetL, OffsetT, OffsetR, and the like) between the target layer (for example, the enhancement layer) and the reference layer (for example, the base layer) derived based on the reference layer correspondence information Based on OffsetB, SRLPW, SRLPH, ScaleFactorX, ScaleFactorY, etc.), the reference image block on the reference layer picture corresponding to the target block on the resampled reference layer picture is determined, and the target block is determined based on the motion information of the reference image block Motion information can be generated. Thereby, the effect which improves the precision of the motion information (temporal motion information) used by the motion prediction between layers can be acquired. In particular, for a sequence in which the corresponding region of the target layer and the reference layer changes in units of pictures, compared to the case where inter-layer motion mapping is performed based on the inter-layer correspondence parameter derived from the reference layer corresponding region information, By performing inter-layer motion mapping based on the inter-layer correspondence parameter derived from the active reference layer corresponding region information (reference layer corresponding region information in units of pictures), more motion information (temporal) used in inter-layer motion prediction This has the effect of further improving the accuracy of motion information. Accordingly, the prediction accuracy of inter-layer motion prediction is also improved, so that the encoding efficiency can be improved.

  Furthermore, in the image decoding device according to the present invention, the reference layer corresponding region information corresponding to each picture is difference information from the reference layer corresponding region information common to the entire target sequence.

  As described above, according to the above configuration, the reference layer corresponding region information in units of pictures is the picture for the reference layer corresponding region that is common in the entire sequence as compared with the case where the information of the reference layer corresponding region is explicitly notified in units of pictures. By notifying the difference information of the size of the reference layer corresponding area in units, it is possible to reduce the amount of code necessary for decoding the reference layer corresponding area information in units of pictures.

Furthermore, the image decoding apparatus according to the present invention includes an inter-layer image prediction decoding unit that decodes an inter-layer image prediction flag indicating whether the prediction method of the prediction unit is inter-layer image prediction.
The inter-layer image prediction decoding means omits decoding of an inter-layer image prediction flag related to inter-layer image prediction that satisfies the predetermined condition.

  As described above, according to the above configuration, it is possible to control whether to explicitly decode the inter-layer image prediction flag corresponding to the target prediction unit. That is, in the case of inter-layer image prediction that satisfies the above-mentioned predetermined condition in the target prediction unit, the decoding of the inter-layer image prediction flag is omitted (that is, the inter-layer image prediction flag is estimated to be 0). The amount of processing related to decoding the prediction flag can be reduced. Moreover, since the amount of codes related to the inter-layer image prediction flag can be reduced, the effect of improving the code efficiency is achieved.

In order to solve the above problems, an image encoding device according to the present invention encodes hierarchically encoded data in which image information relating to images of different quality for each layer is encoded hierarchically, An image encoding device that encodes an image in a target layer,
Reference layer corresponding region information encoding means for encoding reference layer corresponding region information indicating a corresponding region between a target layer and a reference layer;
An inter-layer image prediction constraint flag encoding means for encoding an inter-layer image prediction constraint flag that prohibits inter-layer image prediction satisfying a predetermined condition;
Re-sampling means for generating a re-sampled reference layer picture by associating the image and motion information of the reference layer picture with the picture of the target layer based on the encoded reference layer picture and the reference layer corresponding region information;
A prediction image generating unit that generates a prediction image of each prediction unit constituting the picture of the target layer,
When the inter-layer image prediction constraint flag is true and the prediction method of the prediction unit is inter-layer image prediction, the predicted image generation means performs prediction of the prediction unit by inter-layer image prediction that does not satisfy the predetermined condition. A moving picture coding apparatus for generating a predicted picture.

  As described above, according to the above configuration, the resampled reference layer picture is obtained by associating the image and motion information of the reference layer picture with the picture of the target layer based on the encoded reference layer picture and the reference layer corresponding region information. Therefore, the accuracy of inter-layer image prediction and inter-layer motion prediction can be improved. As a result, the code efficiency can be further improved. Moreover, according to the said structure, since use of the image prediction between layers satisfy | filling the predetermined conditions with low prediction accuracy is prohibited, encoding efficiency can be improved.

  Furthermore, in the image encoding device according to the present invention, the inter-layer image prediction that satisfies the predetermined condition is that in the inter-layer image prediction, the corresponding region on the resample reference layer picture corresponding to the prediction unit and the reference layer Regarding the corresponding region, (1) the left end coordinate of the corresponding region is smaller than the left end coordinate of the reference layer corresponding region, (2) the right end coordinate of the corresponding region is larger than the right end coordinate of the reference layer corresponding region, (3) the above The upper end coordinate of the corresponding region is smaller than the upper end coordinate of the reference layer corresponding region, and (4) the lower end coordinate of the corresponding region is larger than the lower end coordinate of the reference layer corresponding region. It is characterized by.

  As described above, according to the above configuration, use of inter-layer image prediction that refers to an image outside the reference layer corresponding region can be prohibited. Accordingly, since inter-layer image prediction that refers to pixels outside the reference layer corresponding region with low prediction accuracy is not used, an image encoding device with higher encoding efficiency can be realized. Furthermore, according to the above configuration, when the inter-layer image prediction constraint flag is determined, if the flag is true, an image (reference layer) outside the reference layer corresponding region on the resample reference layer picture in the target sequence. Since it is understood that “outside corresponding region” is not referred to when inter-layer image prediction is performed, generation of an image outside the reference layer corresponding region can be omitted when generating a resampled image of the resampled reference layer picture.

  Furthermore, in the image encoding device according to the present invention, the inter-layer image prediction that satisfies the predetermined condition is that in the inter-layer image prediction, the corresponding region on the resample reference layer picture corresponding to the prediction unit and the reference layer Regarding the corresponding region, (1) the right end coordinate of the corresponding region is smaller than the left end coordinate of the reference layer corresponding region, (2) the left end coordinate of the corresponding region is larger than the right end coordinate of the reference layer corresponding region, (3) the above The lower end coordinate of the corresponding region is smaller than the upper end coordinate of the reference layer corresponding region, and (4) the upper end coordinate of the corresponding region is larger than the lower end coordinate of the reference layer corresponding region. It is characterized by.

  As described above, according to the above configuration, it is possible to prohibit the use of inter-layer image prediction that refers only to images outside the reference layer corresponding region. Therefore, since inter-layer image prediction that refers only to pixels outside the reference layer corresponding region with low prediction accuracy is not used, an image encoding device with higher encoding efficiency can be realized.

  As described above, when the inter-layer image prediction constraint flag indicates that the application of inter-layer image prediction that refers to a pixel outside the reference layer corresponding region is not possible, the image decoding device according to the present invention has a reference layer corresponding region with low prediction accuracy. Since inter-layer image prediction that refers to other pixels is not used, there is an effect of improving coding efficiency. In addition, when generating the image rsPicSample of the resample reference picture rsPic, the process of generating pixels outside the reference layer corresponding region (padding process) can be omitted, so that the amount of processing related to the resample process can be reduced. Play.

  As described above, when the inter-layer image prediction constraint flag indicates that application of inter-layer image prediction that refers to a pixel outside the reference layer corresponding region is not applicable, the image encoding device according to the present invention supports reference layer with low prediction accuracy. Since inter-layer image prediction that refers to pixels outside the region is not used, there is an effect of improving the coding efficiency. In addition, when generating the image rsPicSample of the resample reference picture rsPic, the process of generating pixels outside the reference layer corresponding region (padding process) can be omitted, so that the amount of processing related to the resample process can be reduced. Play.

It is a figure for demonstrating the layer structure of the hierarchy coding data which concerns on embodiment of this invention, Comprising: (a) has shown about the hierarchy moving image encoder side, (b) is a hierarchy moving image decoding. The device side is shown. It is a figure for demonstrating the structure of the hierarchy coding data based on embodiment of this invention, (a) is a sequence layer which prescribes | regulates sequence SEQ, (b) is a picture layer which prescribes | regulates picture PICT, ( (c) is a slice layer that defines a slice S, (d) is a slice data layer that defines slice data, (e) is a coding tree layer that defines a coding tree unit included in the slice data, (f) ) Is a diagram illustrating a coding unit layer that defines a coding unit (CU) included in a coding tree. It is an example of the syntax contained in the video parameter set VPS which concerns on this embodiment. It is a figure for demonstrating the corresponding | compatible area | region (reference layer corresponding | compatible area | region) with the image of a target layer, and the image of a reference layer. It is an example of the reference layer corresponding | compatible area | region information which concerns on this embodiment, and an image prediction constraint flag between layers. It is an example of the inter-layer image prediction which refers to the image outside the reference layer corresponding area SRLA. (A) shows a case where both images of the reference layer corresponding region SRLA and the reference layer corresponding non-region NSRLA are referred to at the time of inter-layer image prediction, and (b) is a reference layer corresponding region at the time of inter-layer image prediction. The case where only the image of outside NSRLA is referred is shown. It is an example of the active reference layer designation | designated information which concerns on this embodiment, and active reference layer corresponding | compatible area information. It is another example of the active reference layer corresponding | compatible area information which concerns on this embodiment. It is a figure for demonstrating the active reference layer corresponding | compatible area | region which concerns on this embodiment. It is a conceptual diagram which shows an example of a reference picture list. It is a conceptual diagram which shows the example of a reference picture. It is a functional block diagram which shows the schematic structure of the said hierarchy moving image decoding apparatus. It is the schematic which shows the structure of the image decoding apparatus which concerns on this embodiment. It is the schematic which shows the structure of the inter prediction parameter decoding part which concerns on this embodiment. It is the schematic which shows the structure of the merge prediction parameter derivation | leading-out part which concerns on this embodiment. It is a conceptual diagram which shows the positional relationship of the object block, the object block of a spatial motion vector, and the object block of a temporal motion vector. It is the schematic which shows the structure of the AMVP prediction parameter derivation | leading-out part which concerns on this embodiment. It is the schematic which shows the structure of the resampling part which concerns on this embodiment. It is an example of the resample filter regarding a brightness | luminance. It is an example of the resample filter regarding a color difference. It is a figure which shows an example of the syntax of CU containing the image prediction flag between layers. It is a flowchart which shows the operation | movement which concerns on the modification of the prediction parameter decoding part which concerns on this embodiment. It is a functional block diagram which shows schematic structure of the hierarchy moving image encoder which concerns on one Embodiment of this invention. It is a functional block diagram which shows schematic structure of the image coding apparatus which concerns on this embodiment. It is a functional block diagram which shows the schematic structure of the inter prediction parameter encoding part which concerns on this embodiment. It is a flowchart which shows the operation | movement which concerns on the modification of the prediction parameter encoding part which concerns on this embodiment. It is the figure which showed the structure of the transmitter which mounts the said hierarchy moving image encoder, and the receiver which mounts the said hierarchy moving image decoder. (A) shows a transmission device equipped with a hierarchical video encoding device, and (b) shows a reception device equipped with a hierarchical video decoding device. It is the figure which showed the structure of the recording device carrying the said hierarchy moving image encoder, and the reproducing | regenerating apparatus carrying the said hierarchy moving image decoding apparatus. (A) shows a recording device equipped with a hierarchical video encoding device, and (b) shows a playback device equipped with a hierarchical video decoding device. It is a flowchart which shows operation | movement of the layer image mapping part which concerns on this embodiment. It is a flowchart which shows operation | movement of the layer image mapping part which concerns on a prior art. It is a schematic diagram which shows derivation | leading-out of the reference pixel position corresponding to the pixel on NSRLA outside the reference layer corresponding | compatible area | region on resample reference layer picture rsPic, (a) is a derivation example of the reference pixel position which concerns on a prior art, ( b) is an example of deriving the reference pixel position according to the present invention. It is a figure for demonstrating the resample pixel of the non-reference layer corresponding | compatible area | region NSRLA on the resample reference layer picture rsPic, (a) shows the example in a prior art, (b) is an example in this invention. It is another example of the reference layer corresponding | compatible area information which concerns on this embodiment. It is another example of the active reference layer corresponding | compatible area information which concerns on this embodiment. It is another example of the active reference layer corresponding | compatible area information which concerns on this embodiment.

The hierarchical moving picture decoding apparatus 1 and the hierarchical moving picture encoding apparatus 2 according to an embodiment of the present invention will be described as follows based on FIGS.

〔Overview〕
A hierarchical video decoding device (image decoding device) 1 according to the present embodiment decodes encoded data that has been hierarchically encoded by a hierarchical video encoding device (image encoding device) 2. Hierarchical coding is a coding scheme that hierarchically encodes moving images from low quality to high quality. Hierarchical coding is standardized in SVC and SHVC, for example. Note that the quality of a moving image here widely means an element that affects the appearance of a subjective and objective moving image. The quality of the moving image includes, for example, “resolution”, “frame rate”, “image quality”, and “pixel representation accuracy”. Therefore, hereinafter, if the quality of the moving image is different, it means that, for example, “resolution” is different, but it is not limited thereto. For example, in the case of moving images quantized in different quantization steps (that is, moving images encoded with different encoding noises), it can be said that the quality of moving images is different from each other.

  In addition, the hierarchical coding technology is (1) spatial scalability, (2) temporal scalability, (3) SNR (Signal to Noise Ratio) scalability, and (4) view scalability from the viewpoint of the type of information to be layered. May be classified. Spatial scalability is a technique for hierarchizing resolution and image size. Time scalability is a technique for layering at a frame rate (number of frames per unit time). SNR scalability is a technique for layering in coding noise. Also, view scalability is a technique for hierarchizing at the viewpoint position associated with each image.

  Prior to detailed description of the hierarchical video encoding device 2 and the hierarchical video decoding device 1 according to the present embodiment, first, (1) the hierarchical video encoding device 2 generates and the hierarchical video decoding device 1 performs decoding. The layer structure of the hierarchically encoded data to be performed will be described, and then (2) a specific example of the data structure that can be adopted in each layer will be described.

[Layer structure of hierarchically encoded data]
Here, the encoding and decoding of hierarchically encoded data will be described with reference to FIG. FIG. 1 is a diagram schematically illustrating a case where a moving image is hierarchically encoded / decoded by three layers of a lower layer L3, a middle layer L2, and an upper layer L1. That is, in the example shown in FIGS. 1A and 1B, among the three layers, the upper layer L1 is the highest layer and the lower layer L3 is the lowest layer.

  In the following, a decoded image corresponding to a specific quality that can be decoded from hierarchically encoded data is referred to as a decoded image of a specific hierarchy (or a decoded image corresponding to a specific hierarchy) (for example, an upper layer L1). Decoded image POUT # A).

  FIG. 1A shows a hierarchical video encoding device 2 # A-2 # C that generates encoded data DATA # A-DATA # C by hierarchically encoding input images PIN # A-PIN # C, respectively. Is shown. FIG. 1B illustrates a hierarchical video decoding device 1 # A that generates decoded images POUT # A to POUT # C by decoding encoded data DATA # A to DATA # C that are encoded hierarchically. 1 # C is shown.

  First, the encoding device side will be described with reference to FIG. The input images PIN # A, PIN # B, and PIN # C that are input on the encoding device side have the same original image but different image quality (resolution, frame rate, image quality, and the like). The image quality decreases in the order of the input images PIN # A, PIN # B, and PIN # C.

  The hierarchical video encoding apparatus 2 # C of the lower hierarchy L3 encodes the input image PIN # C of the lower hierarchy L3 to generate encoded data DATA # C of the lower hierarchy L3. Basic information necessary for decoding the decoded image POUT # C of the lower layer L3 is included (indicated by “C” in FIG. 1). Since the lower layer L3 is the lowest layer, the encoded data DATA # C of the lower layer L3 is also referred to as basic encoded data.

  Further, the hierarchical video encoding apparatus 2 # B of the middle hierarchy L2 encodes the input image PIN # B of the middle hierarchy L2 with reference to the encoded data DATA # C of the lower hierarchy, and performs the middle hierarchy L2 Encoded data DATA # B is generated. In addition to the basic information “C” included in the encoded data DATA # C, additional data necessary for decoding the decoded image POUT # B of the intermediate hierarchy is added to the encoded data DATA # B of the intermediate hierarchy L2. Information (indicated by “B” in FIG. 1) is included.

  Further, the hierarchical video encoding apparatus 2 # A of the upper hierarchy L1 encodes the input image PIN # A of the upper hierarchy L1 with reference to the encoded data DATA # B of the intermediate hierarchy L2 to Encoded data DATA # A is generated. The encoded data DATA # A of the upper layer L1 is used to decode the basic information “C” necessary for decoding the decoded image POUT # C of the lower layer L3 and the decoded image POUT # B of the middle layer L2. In addition to the necessary additional information “B”, additional information (indicated by “A” in FIG. 1) necessary for decoding the decoded image POUT # A of the upper layer is included.

  As described above, the encoded data DATA # A of the upper layer L1 includes information related to decoded images having a plurality of different qualities.

  Next, the decoding device side will be described with reference to FIG. On the decoding device side, the decoding devices 1 # A, 1 # B, and 1 # C corresponding to the layers of the upper layer L1, the middle layer L2, and the lower layer L3 are encoded data DATA # A and DATA # B, respectively. , And DATA # C are decoded to output decoded images POUT # A, POUT # B, and POUT # C.

  It is also possible to reproduce a moving image having a specific quality by extracting a part of the information of the upper layer encoded data and decoding the extracted information in a lower specific decoding device.

  For example, the hierarchy decoding apparatus 1 # B of the middle hierarchy L2 receives information necessary for decoding the decoded image POUT # B from the hierarchy encoded data DATA # A of the upper hierarchy L1 (that is, the hierarchy encoded data DATA # A decoded image POUT # B may be decoded by extracting “B” and “C”) included in A. In other words, on the decoding device side, the decoded images POUT # A, POUT # B, and POUT # C can be decoded based on information included in the hierarchically encoded data DATA # A of the upper hierarchy L1.

  The hierarchical encoded data is not limited to the above three-layer hierarchical encoded data, and the hierarchical encoded data may be hierarchically encoded with two layers or may be hierarchically encoded with a number of layers larger than three. Good.

  Also, a part or all of the encoded data related to the decoded image of a specific hierarchy is encoded independently of the other hierarchy, and it is not necessary to refer to information of the other hierarchy when decoding the specific hierarchy. Hierarchically encoded data may be configured as described above. For example, in the example described above with reference to FIGS. 1A and 1B, it has been described that “C” and “B” are referred to for decoding the decoded image POUT # B, but the present invention is not limited thereto. It is also possible to configure the hierarchically encoded data so that the decoded image POUT # B can be decoded using only “B”. For example, it is possible to configure a hierarchical video decoding apparatus that receives the hierarchically encoded data composed only of “B” and the decoded image POUT # C for decoding the decoded image POUT # B.

  When SNR scalability is realized, the same original image is used as the input images PIN # A, PIN # B, and PIN # C, and the decoded images POUT # A, POUT # B, and POUT # C have different image quality. Hierarchically encoded data can also be generated so that In that case, the lower layer hierarchical video encoding device generates hierarchical encoded data by quantizing the prediction residual using a larger quantization width than the upper layer hierarchical video encoding device. To do.

  In this document, the following terms are defined for convenience of explanation. The following terms are used to indicate the following technical matters unless otherwise specified.

  Upper layer: A layer positioned higher than a certain layer is referred to as an upper layer. For example, in FIG. 1, the upper layers of the lower layer L3 are the middle layer L2 and the upper layer L1. The decoded image of the upper layer means a decoded image with higher quality (for example, high resolution, high frame rate, high image quality, etc.).

  Lower layer: A layer located lower than a certain layer is referred to as a lower layer. For example, in FIG. 1, the lower layers of the upper layer L1 are the middle layer L2 and the lower layer L3. Further, the decoded image of the lower layer refers to a decoded image with lower quality.

  Target layer: A layer that is the target of decoding or encoding.

  Reference layer: A specific lower layer referred to for decoding a decoded image corresponding to a target layer is referred to as a reference layer.

  In the example shown in FIGS. 1A and 1B, the reference layers of the upper hierarchy L1 are the middle hierarchy L2 and the lower hierarchy L3. However, the present invention is not limited to this, and the hierarchically encoded data can be configured so that it is not necessary to refer to all of the lower layers in decoding of the specific layer. For example, the hierarchical encoded data can be configured such that the reference layer of the upper hierarchy L1 is either the middle hierarchy L2 or the lower hierarchy L3.

  Basic layer: A layer located at the lowest layer is referred to as a basic layer. The decoded image of the base layer is the lowest quality decoded image that can be decoded from the encoded data, and is referred to as a basic decoded image. In other words, the basic decoded image is a decoded image corresponding to the lowest layer. The partially encoded data of the hierarchically encoded data necessary for decoding the basic decoded image is referred to as basic encoded data. For example, the basic information “C” included in the hierarchically encoded data DATA # A of the upper hierarchy L1 is the basic encoded data.

  Enhancement layer: The upper layer of the base layer is referred to as an enhancement layer.

  Layer identifier: The layer identifier is for identifying a hierarchy, and corresponds to the hierarchy one-to-one. The hierarchically encoded data includes a hierarchical identifier used for selecting partial encoded data necessary for decoding a decoded image of a specific hierarchy. A subset of hierarchically encoded data associated with a layer identifier corresponding to a specific layer is also referred to as a layer representation.

  In general, for decoding a decoded image of a specific hierarchy, a layer expression of the hierarchy and / or a layer expression corresponding to a lower layer of the hierarchy is used. That is, in decoding the decoded image of the target layer, layer representation of the target layer and / or layer representation of one or more layers included in a lower layer of the target layer are used.

  Inter-layer prediction: Inter-layer prediction is based on a syntax element value included in a layer expression of a layer (reference layer) different from the layer expression of the target layer, a value derived from the syntax element value, and a decoded image. It is to predict the syntax element value of the target layer, the encoding parameter used for decoding of the target layer, and the like. Inter-layer prediction in which information related to motion prediction is predicted from reference layer information is sometimes referred to as inter-layer motion information prediction. In addition, inter-layer prediction predicted from a lower layer decoded image may be referred to as inter-layer image prediction (or inter-layer texture prediction). Note that the hierarchy used for inter-layer prediction is, for example, a lower layer of the target layer. In addition, performing prediction within a target layer without using a reference layer may be referred to as intra-layer prediction.

  Note that the above terms are for convenience of explanation until they are tired, and the above technical matters may be expressed by other terms.

[Data structure of hierarchically encoded data]
Hereinafter, a case where HEVC and its extension method are used as an encoding method for generating encoded data of each layer will be exemplified. However, the present invention is not limited to this, and the encoded data of each layer may be generated by an encoding method such as MPEG-2 or H.264 / AVC.

  Further, the lower layer and the upper layer may be encoded by different encoding methods. Also, the encoded data of each layer may be supplied to the hierarchical video decoding device 1 via different transmission paths, or may be supplied to the hierarchical video decoding device 1 via the same transmission path. .

  For example, when transmitting ultra-high-definition video (moving image, 4K video data) with a base layer and one extended layer in a scalable encoding, the base layer downscales 4K video data, and interlaced video data. It may be encoded by MPEG-2 or H.264 / AVC and transmitted over a television broadcast network, and the enhancement layer may encode 4K video (progressive) with HEVC and transmit over the Internet.

  FIG. 2 is a diagram illustrating an example of the data structure of hierarchically encoded data DATA (in FIG. 1, for example, hierarchically encoded data DATA # B).

A hierarchical structure of data in the hierarchically encoded data DATA is shown in FIG. The hierarchically encoded data DATA illustratively includes a sequence and a plurality of pictures constituting the sequence.
2A to 2F 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 slice data. It is a figure which shows the encoding unit layer which prescribes | regulates the encoding tree layer (Coding Unit; CU) contained in the encoding tree unit and Coding Tree Unit (CTU) which are contained, and the coding tree unit CTU. .

(Sequence layer)
In the sequence layer, a set of data referred to by the hierarchical video decoding device 1 for decoding the sequence SEQ to be processed (hereinafter also referred to as a target sequence) is defined. As shown in FIG. 2A, the sequence SEQ includes a video parameter set VPS (Video Parameter Set), a sequence parameter set SPS (Sequence Parameter Set), a picture parameter set PPS (Picture Parameter Set), a picture PICT, It includes supplemental enhancement information (SEI). Here, the value indicated after # indicates the layer ID. FIG. 2 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 limited to 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. An example of syntax included in the VPS will be described with reference to FIG. For example, the VPS includes vps_max_layers_minus1 that defines the number of layers indicated by SYNVPS01 in FIG. Further, in the VPS extension data (SYNVPS02 on FIG. 3A), layer identifier designation information layer_id_nuh [i] (SYNVPS03 on FIG. SYNS_VPS (b)) that associates the layer identifier layer_id and layer i defined on the NAL unit header. )including. Hereinafter, for the sake of simplicity, layer i represents a layer having layer identifier layer_id = i unless otherwise specified. Further, the VPS extension data (SYNVPS02 on FIG. 3A) includes reference layer designation information (SYNVPS04 on FIG. 3B) that defines a reference layer other than the target layer referred to in the target layer. It is. Specifically, the reference layer designation information includes a layer dependency flag direct_dependency_flag [i] [j]. If the layer dependency flag direct_dependency_flag [i] [j] is 1, the target layer i refers to the reference layer j, and if the layer dependency flag is 0, the target layer i does not refer to the reference layer j Represents. In addition, the number of reference layers referred to by the target layer i (also called the number of inter-layer prediction reference layers) NumDirectRefLayers [i] is determined from the number of non-zero layer dependency flags direct_dependency_flag [i] [j] corresponding to the target layer i. . Also, a reference layer RefLayerId [i] [] that is a layer to which the target layer i refers is derived. RefLayerId [i] [] is a list storing the layer IDs of reference layers referred to by the target layer i, and has NumDirectRefLayers [i] elements. When the layer dependency flag direct_dependency_flag [i] [j] is 1, the layer dependency type direct_dependency_type [i] [j] (SYNVPS05 on FIG. 3B) is further included in the VPS. The layer dependency type direct_dependency_type [i] [j] is (1) an inter-layer image prediction presence / absence flag SamplePredEnableFlag [i] [j] indicating whether or not there is inter-layer image prediction in which the target layer i refers to the reference layer j, (2) Inter-layer motion prediction presence / absence flag MotionPredEnableFlag [i] [j] indicating presence / absence of inter-layer motion prediction in which the target layer i refers to the reference layer j, (3) Reference layer that the target layer i refers to for inter-layer image prediction (Also referred to as the number of inter-layer image prediction reference layers) NumSamplePredRefLayers [i], and (4) the number of reference layers that the target layer i refers to for inter-layer motion prediction (also referred to as the number of inter-layer motion prediction reference layers) This syntax is used to derive parameters such as NumMotionPredRefLayers [i]. Here, the inter-layer image prediction presence / absence flag SamplePredEnableFlag [i] [j] indicating the presence / absence of inter-layer image prediction in which the target layer i refers to the reference layer j is derived by, for example, the following equation (F-1) Is true indicates that there is an inter-layer image prediction in which the target layer i refers to the reference layer j, and a value of false indicates that there is no inter-layer image prediction.

SamplePredEnableFlag [i] [j] = ((direct_dependency_type [i] [j] + 1) &1); (F-1)
In addition, the inter-layer motion prediction presence / absence flag MotionPredEnableFlag [i] [j] indicating the presence / absence of inter-layer motion prediction in which the target layer i refers to the reference layer j is derived by the following equation (F-2), for example, When true, the target layer i indicates that there is an inter-layer motion prediction referring to the reference layer j, and when the value is false, it indicates that there is no inter-layer motion prediction.

MotionPredEnableFlag [i] [j] =
(((direct_dependency_type [i] [j] + 1) & 2) >>1); (F-2)
The number of inter-layer image prediction reference layers NumSamplePredRefLayers [i] is determined from the number of non-zero inter-layer image prediction presence / absence flags SamplePredEnableFlag [i] [j] corresponding to the target layer i. Similarly, the inter-layer motion prediction reference layer number NumMotionPredRefLayers [i] is determined from the number of non-zero inter-layer motion prediction presence / absence flags MotionPredEnableFlag [i] [j] corresponding to the target layer i.

  Further, based on the inter-layer image prediction presence / absence flag SamplePredEnableFlag [i] [j], an inter-layer image prediction reference layer index SamplePredRefLayerId [i] for identifying a layer identifier of a reference layer used in inter-layer image prediction in each layer. ] [sIdx] and inter-layer motion prediction presence / absence flag MotionPredEnableFlag [i] [j], the inter-layer motion prediction reference layer index for specifying the layer identifier of the reference layer used in the inter-layer motion prediction in each layer MotionPredRefLayerId [i] [mIdx] is derived by the following equation (F-3).

for (i = 1; mIdx = 0, sIdx = 0; i <= vps_max_layers_minus1; i ++) {
iNuhLid = layer_id_in_nuh [i];
for (j = 0; j <i; j ++) {
if (MotionPredEnableFlag [iNuhId] [j])
MotionPredRefLayerId [iNuhId] [mIdx ++] = layer_id_in_nuh [j];
if (SamplePredEnableFlag [iNuhId] [j])
SamplePredRefLayerId [iNuhId] [sIdx ++] = layer_id_in_nuh [j];
}
} (F-3)
In the sequence parameter set SPS, a set of encoding parameters referred to by the hierarchical video decoding device 1 for decoding the target sequence is defined. For example, the horizontal width PW and vertical width PH of the picture in the target sequence are defined. The SPS defines reference layer corresponding region information indicating which region on the target picture curPic (or the resample reference layer picture rsPic) of the target layer corresponds to the reference layer picture rlPic. A plurality of SPSs may exist in the encoded data. In that case, the SPS used for decoding is selected from a plurality of candidates for each target sequence. An SPS used for decoding a specific sequence is also called an active SPS. In the following, unless otherwise specified, it means an active SPS for the target sequence.

  Prior to the description of the reference layer corresponding region information, the corresponding region (reference layer corresponding region) between the picture of the target layer and the picture of the reference layer will be described with reference to FIG. RlPic in the figure is a reference layer picture (reference layer picture) having an image size of vertical width RLPH and horizontal width RLPW. RsPic in the figure is a picture (resample reference layer picture) rsPic obtained by mapping the reference layer picture rlPic to a picture of a target layer having an image size of the vertical width PH and the horizontal width PW. SRLA (gray portion) in the drawing is an area (reference layer corresponding area) corresponding to the reference layer picture rlPic on the picture of the target layer, and has a size of the vertical width SRLPH and the horizontal width SRLPW. NSRLA in the figure is an area outside the reference layer corresponding area SRLA (referred to as “outside reference layer corresponding area”). Offset L in the figure represents an offset in the horizontal direction (x direction) between the upper left pixel of the reference layer corresponding area SRLA and the upper left pixel of the picture of the target layer (or the resample reference picture rsPic). OffsetT in the drawing represents an offset in the vertical direction (y direction) between the upper left pixel of the reference layer corresponding region SRLA and the upper left pixel of the picture of the target layer (or the resample reference picture rsPic). OffsetR in the drawing represents an offset in the horizontal direction (x direction) between the lowermost right pixel of the reference layer corresponding region SRLA and the lowermost right pixel of the picture of the target layer (or the resample reference picture rsPic). OffsetB in the figure represents an offset in the vertical direction (y direction) between the lowermost right pixel of the reference layer corresponding region SRLA and the lowermost right pixel of the picture of the target layer (or the resample reference picture rsPic).

  The SPS includes SPS extension data sps_extension () shown in SYNSPS01 on FIG. Furthermore, the SPS extension data sps_extension () includes a syntax group indicated by SYNSPS02 on FIG. 5B as reference layer corresponding region information. Note that the reference layer corresponding region information included in the SPS is a reference layer corresponding region that is common (standard) in the entire sequence. When the reference layer corresponding area changes for each picture, reference layer corresponding area information (active reference layer corresponding area information described later) corresponding to each picture is notified.

  scaled_ref_layer_offsets_param_present_flag is a flag (reference layer corresponding region information group presence / absence flag) indicating whether or not there is reference layer corresponding region information of the target picture curPic of the target layer curLayerId and the number of reference layers NumDirectRefLayers [curLayerId]. It indicates that there are several layers of reference layer corresponding region information. If the value is false, it indicates that there is no reference layer corresponding region information. In the example of SYNPSPS02 in FIG. 5B, when NumDirectRefLayers [curLyaerId] is greater than 0, the reference layer corresponding area information group presence / absence flag is explicitly notified, and when NumDirectRefLayers [curLyaerId] is 0, the reference layer corresponding area The information group presence / absence flag is estimated to be 0. Note that the conventional technology explicitly includes the syntax num_scaled_ref_layer_offsets that indicates how many reference layer corresponding region information exist even though the number of reference layers NumDirectRefLayers [curLayer] of the target layer is known. It was. On the other hand, in the present invention, when the reference layer corresponding region information group presence / absence flag is true, the reference layer corresponding region information (NumDirectRefLayers [curLyaerId] pieces of reference layer corresponding region information) of each reference layer is explicitly notified. . Accordingly, it is possible to reduce the amount of codes related to the reference layer corresponding region information as compared with the conventional technique that notifies the syntax num_scaled_ref_layer_offsets indicating how many reference layer corresponding region information is present.

  In addition, it is good also as a structure of SYNPSPS02A shown to Fig.33 (a) instead of SYNPSPS02 on FIG.5 (b). That is, when NumDirectRefLayers [curLyaerId] is greater than 1, a reference layer corresponding region information group presence / absence flag is explicitly notified, and when NumDirectRefLayers [curLyaerId] is 0, it is estimated that the reference layer corresponding region information group presence / absence flag is 0. When NumDirectRefLayers [curLyaerId] is 1 (when NumDirectRefLayrs [curlayerId] is less than 2), it is estimated that the reference layer corresponding region information presence / absence flag is 1. Accordingly, when the number of reference layers is one as compared with the example of SYNSPS02 in FIG. 5B, there is no need to explicitly notify the reference layer corresponding region information group presence / absence flag, and the reference layer corresponding region information group It is possible to reduce the code amount related to the presence / absence flag. Further, when NumDirectRefLayers [curLyaerId] is 0, the flag of the loop part by NumDirectRefLayers [curLyaerId] is not encoded. However, in order to more clearly indicate that these flags are not encoded, the reference layer corresponding region information group presence / absence flag may be estimated to be zero.

  In the configuration of FIG. 33A, when NumDirectRefLayers [curLyaerId] is greater than 1, the reference layer corresponding region information does not need to be encoded by notifying the reference layer corresponding region information group presence / absence flag. The amount of codes can be reduced. Further, as described later, by not encoding the reference layer corresponding region information presence / absence flag for each reference layer, each syntax (scaled_ref_layer_left_offset [i], scaled_ref_layer_top_offset [i], scaled_ref_layer_right_offset [i], scaled_ref_layer_bottom_offset [i ]) Can be reduced. Moreover, it is good also as a structure of SYNPSPS02B shown in FIG.33 (b). In this case, the reference layer corresponding region information group presence / absence flag is not included, and NumDirectRefLayers [curLayer] reference layer corresponding region information is explicitly notified. Similarly, it is possible to reduce the amount of codes related to the reference layer corresponding region information as compared with the conventional technique that notifies the syntax num_scaled_ref_layer_offsets indicating how many reference layer corresponding region information exists.

  scaled_ref_layer_offset_present_flag [i] is a flag indicating the presence / absence of reference layer corresponding area information between the target layer curLayerId and the reference layer RefLayerId [curLayerId] [i] (referred to as reference layer corresponding area information presence / absence flag), and the value is true In addition, as reference layer corresponding area information, the following four syntaxes scaled_ref_layer_left_offset [i], scaled_ref_layer_top_offset [i], scaled_ref_layer_right_offset [i], and scaled_ref_layer_bottom_offset [i] are explicitly included. The syntax values are each estimated to be zero. The definition of each syntax is as follows. When the value of the reference layer corresponding region information group presence / absence flag is false, the value of the reference layer corresponding region information presence / absence flag is estimated to be zero.

  scaled_ref_layer_left_offset [i] is a predetermined value between the upper left pixel of the reference layer corresponding area SRLA on the resampled i-th reference layer RefLayerId [curLayerId] [i] and the upper left pixel of the target picture curPic used for inter-layer prediction This is an offset in the horizontal direction (x direction) in pixel units.

  scaled_ref_layer_top_offset [i] is a predetermined value between the upper left pixel of the reference layer corresponding area SRLA on the resampled i-th reference layer RefLayerId [curLayerId] [i] and the upper left pixel of the target picture curPic used for inter-layer prediction. This is an offset in the vertical direction (y direction) in pixel units.

  scaled_ref_layer_right_offset [i] is the rightmost lower right pixel of the reference layer corresponding region SRLA on the resampled i-th reference layer RefLayerId [curLayerId] [i] and the lowermost right luminance pixel of the target picture curPic used for inter-layer prediction It is an offset in the horizontal direction (x direction) of a predetermined pixel unit between them.

  scaled_ref_layer_bottom_offset [i] is used for inter-layer prediction, between the lowest right pixel of the reference layer corresponding region SRLA on the resampled i-th reference layer RefLayerId [curLayerId] [i] and the lower right pixel of the target picture curPic Is an offset in the vertical direction (y direction) of a predetermined pixel unit.

  Therefore, when the reference layer corresponding region information presence / absence flag is 0, it is possible to reduce the amount of code related to each syntax (scaled_ref_layer_left_offset [i], scaled_ref_layer_top_offset [i], scaled_ref_layer_right_offset [i], scaled_ref_layer_bottom_offset [i]). .

  Each offset OffsetL, OffsetT, OffsetR, and OffsetB in FIG. 4 is the syntax scaled_ref_layer_left_offset [dRlIdx], scaled_ref_layer_top_offset [dRlIdx] included in the reference layer corresponding region information between the target layer curLayerId and the reference layer RefLayerId [curLayerId] [dRlIdx]. , Scaled_ref_layer_right_offset [dRlIdx] and scaled_ref_layer_bottom_offset [dRlIdx] are derived by the following equations (G-1) to (G-4).

OffsetL = scaled_ref_layer_left_offset [dRlIdx] <<sample_unit_bit; (G-1)
OffsetT = scaled_ref_layer_top_offset [dRlIdx] <<sample_unit_bit; (G-2)
OffsetR = scaled_ref_layer_right_offset [dRlIdx] <<sample_unit_bit; (G-3)
OffsetB = scaled_ref_layer_bottom_offset [dRlIdx] <<sample_unit_bit; (G-4)
Here, sample_unit_bit is a value representing a predetermined pixel unit represented by a power of 2 as a logarithmic value with 2 as the base. For example, when 2 pixels are used as a unit, sample_unit_bit = 1. In addition, when 2 ^ N pixels (the value of N is 0 or more) is used as a unit, sample_unit_bit = N. Note that sample_unit_bit may be predetermined between the image decoding apparatus and the image encoding apparatus, or may be notified in a parameter set such as SPS. OffsetL is also called ScaledRefLayerLeftOffset, OffsetT is also called ScaledRefLayerTopOffset, OffsetR is also called ScaledRefLayerRightOffset, and OffsetB is also called ScaledRefLayerBottomOffset.

  Conversely, the values of each syntax scaled_ref_layer_left_offset [dRlIdx], scaled_ref_layer_top_offset [dRlIdx], scaled_ref_layer_right_offset [dRlIdx], scaled_ref_layer_bottom_offset [dRlIdx] are equivalent to (G-1) ~ (G-4) ) To (I-4).

scaled_ref_layer_left_offset [dRlIdx] = OffsetL >>sample_unit_bit; (I-1)
scaled_ref_layer_top_offset [dRlIdx] = OffsetT >>sample_unit_bit; (I-2)
scaled_ref_layer_right_offset [dRlIdx] = OffsetR >>sample_unit_bit; (I-3)
scaled_ref_layer_bottom_offset [dRlIdx] = OffsetB >>sample_unit_bit; (I-4)
Further, the value of scaled_ref_layer_offset_present_flag [dRlIdx] is set to 0 when all the syntax values determined by the expressions (I-1) to (I-4) are 0, and is set to 1 otherwise. .

  Also, the horizontal width SRLPW and the vertical width SRLPH of the reference layer corresponding region SRLA in FIG. 4 are derived by, for example, the following equations (G-5) to (G-6).

SRLPW = PW-OffsetL-OffsetR; (G-5)
SRLPH = PH-OffsetT-OffsetB; (G-6)
PW is also called PicWidthInSamplesL, PH is also called PicHeightInSamplesL, SRLPW is also called ScaledRefLayerPicWidthInSamplesL, and SRLPH is also called ScaledRefLayerPicHeightInSamplesL.

  Further, the size ratio ScaleFactorX of the reference layer picture rlPic with respect to the width of the reference layer corresponding area SRLA in FIG. 4 and the size ratio ScaleFactorY of the reference layer picture rlPic with respect to the vertical width of the reference layer corresponding area SRLA are as follows: It is derived by the equations (G-7) to (G-8).

ScaleFactorX = ((RLPW << nosf_bit) + (SRLPW >> 1)) / SRLPW; (G-7)
ScaleFactorY = ((RLPH << nosf_bit) + (SRLPH >> 1)) / SRLPH; (G-8)
Here, nosf_bit represents the bit accuracy of the horizontal width size ratio ScaleFactorX and the vertical width size ratio ScaleFactorY between the reference layer corresponding region SRLA and the reference layer picture rlPic in FIG. 4, and is set to, for example, nosf_bit = 16. Also, the horizontal width RLPW of the reference layer picture rlPic is also called RefLayerPicWidthInSamplesL, and the vertical width RLPH of the reference layer picture rlPic is also called RefLayerPicHeightInSamplesL.

(About the inter-layer image prediction constraint flag)
Furthermore, the SPS extension data sps_extension () includes an inter-layer image prediction constraint flag inter_layer_sample_pred_constraint_flag shown in SYNSPS03 in FIG. When the value of the inter-layer image prediction constraint flag inter_layer_sample_pred_constraint_flag is true, an inter-layer image that refers to an image outside the reference layer corresponding region SRLA on the resample reference layer picture rsPic in all prediction units PBX on the target picture curPic Indicates that the use of prediction is prohibited. If the value is false, between all layers that refer to images outside the reference layer corresponding region SRLA on the resampled reference layer picture rsPic in all prediction blocks PBX on the target picture curPic Indicates that the use of image prediction is allowed.

  Whether or not the inter-layer image prediction constraint flag is explicitly included in the SPS extension data is determined based on a flag ScaledRefLayerOffsetsPresentFlag indicating that at least one reference layer corresponding region information shown in SYNSPS02 in FIG. 5 is included. ScaledRefLayerOffsetsPresentFlag is derived by a logical sum with the value of the reference layer corresponding region presence flag of each layer.

ScaledRefLayerOffsetsPresentFlag | = scaled_ref_layer_present_flag [i];
When the value of ScaledRefLyaerOffsetsPresentFlag is true (1), the inter-layer image prediction constraint flag inter_layer_sample_pred_constraint_flag is included in the SPS extension data. When the value is false, the value is estimated to be false (0).

  Note that ScaledRefLayerOffsetsPresentFlag may be derived from the sum of the values of the reference layer corresponding region presence flag of each layer.

ScaledRefLayerOffsetsPresentFlag + = scaled_ref_layer_present_flag [i];
The inter-layer image prediction constraint flag is included in the SPS extension data when the value of the reference layer corresponding region information group presence / absence flag scaled_ref_layer_offsets_param_present_flag is true (1), and is not included in the SPS extension data when false. It may be estimated as false (0). Thereby, the calculation related to the derivation of ScaledRefLayerOffsetsPresentFlag can be omitted.

  Note that the inter-layer image prediction constraint flag may be notified for each reference layer. In addition, when the inter-layer image prediction constraint flag is not explicitly included in the parameter set and the reference layer corresponding region information is included in the parameter set (VPS, SPS, PPS, SH, etc.), the inter-layer image prediction constraint flag The value of may be set to 1. That is, when there is reference layer corresponding region information, use of inter-layer image prediction that refers to an image outside the reference layer corresponding region SRLA on the resample reference layer picture rsPic is always prohibited. In this case, there is an effect of omitting decoding / encoding of codes related to the inter-layer image prediction constraint flag and improving encoding efficiency.

  Here, the merit of introducing a flag (inter-layer image prediction constraint flag) indicating prohibition of use of inter-layer image prediction that refers to an image outside the reference layer corresponding region SRLA will be described with reference to FIG. To do. In FIG. 4, curPic indicates a target picture, rsPic indicates a resample reference layer picture, rlPic indicates a reference layer picture, SRLA indicates a reference layer corresponding area, and NSRLA indicates an area outside the reference layer corresponding area SRLA. An area (outside the reference layer corresponding area) is shown. In the prior art, in the generation of the resampled image rsPicSample of the resample reference layer picture rsPic, the pixels in the reference layer corresponding region SRLA have corresponding pixels on the reference layer picture rlPic, and therefore a predetermined resample filter (up (Also called a sampling filter). On the other hand, there is no corresponding pixel on the reference layer picture rlPic in the portion of the NSRLA portion outside the reference layer corresponding region. Therefore, (1) the pixels in the NSRLA portion outside the reference layer corresponding region are padded (copied) with the border pixels of the reference layer corresponding region SRLA obtained by resampling that are closest, or (2) the reference layer compatible The pixel of the part outside the area NSRLA replaces the coordinate (xP, yP) of the pixel with the coordinate (xP ', yP') of the boundary pixel of the closest reference layer corresponding area, and coordinates (xP ', yP) of the boundary pixel It is generated by deriving the position (xRL, yRL) of the reference pixel of the reference layer picture rlPic corresponding to ') and applying a predetermined resample filter around the position of the reference pixel. Therefore, inter-layer image prediction that refers to pixels only in the reference layer corresponding region SRLA has pixels corresponding to the reference layer picture rlPic, leading to high prediction accuracy and improved coding efficiency. Since inter-layer image prediction that refers to NSRA pixels has low prediction accuracy, conversely, it may lead to a decrease in coding efficiency.

  Therefore, by prohibiting the use of inter-layer image prediction that refers to an image outside the reference layer corresponding region SRLA, it is possible to realize an image decoding device and an image encoding device with higher encoding efficiency. On the image decoding device side, when the inter-layer image prediction constraint flag inter_layer_sample_pred_flag is decoded, if the flag is true, an image outside the reference layer corresponding region SRLA on the resample reference layer picture rsPic in the target sequence (Reference layer-corresponding non-region NSRLA) is not referenced during inter-layer image prediction, so generation of resampled reference layer picture rsPic resampled image rsPicSample is omitted It becomes possible to do. Therefore, it is possible to simplify the resampling process and to reduce the memory required for holding the NSRLA image outside the reference layer corresponding area.

(About inter-layer image prediction that refers to an image outside the reference layer corresponding region)
In the following, referring to FIG. 6A, in inter-layer image prediction, the corresponding region RBX on the resample reference layer picture rsPic corresponding to a certain prediction unit PBX on the target picture curPic is referred to from the reference layer corresponding region SRLA. A condition for referring to the outer image will be described. In the figure, curPic represents a target picture, rlPic represents a reference layer picture, rsPic represents a resample reference layer picture, and SRLA represents a reference layer corresponding area. In the figure, the corresponding region (reference region) on the resample reference layer picture rsPic corresponding to the prediction unit PBX (X = 1... 4) is RBX (X = 1... 4). The vertical width of the prediction unit PBX is hPb and the horizontal width wPb.

  (A1) When the left end coordinate (xP) of the corresponding region is smaller than the left end coordinate (offsetL) of the reference layer corresponding region SRLA (RB1 in FIG. 6A), that is, when the following equation (H-1) is satisfied is there.

xP <max (0, OffsetL) (H-1)
Here, the reason for the calculation of max is that when the left end coordinate of the reference layer corresponding region SRLA is a negative value (when offsetL is a negative value), correction is made to the left end coordinate (0) of the resample reference layer picture rsPic. It is.

  (A2) When the right end coordinate (xP + wPb-1) of the corresponding region is larger than the right end coordinate (PW-OffsetR-1) of the reference layer corresponding region SRLA (RB3 in FIG. 6A), that is, This is the case where H-2) is satisfied.

xP + wPb-1> min (PW-1, PW-OffsetR-1) (H-2)
Here, the reason for the calculation of min is that the right end coordinate of the reference layer corresponding region SRLA is larger than the right end coordinate of the resample reference layer picture rsPic (if offsetR is a negative value), the right end of the resample reference layer picture rsPic This is to correct the coordinates (PW-1). Formula (H-2) can also be expressed as (H-2 ′).

xP + wPb> min (PW, PW-OffsetR) (H-2 ')
(A3) When the upper end coordinate (yP) of the corresponding region is smaller than the upper end coordinate (offsetT) of the reference layer corresponding region SRLA (RB2 in FIG. 6A), that is, when the following equation (H-3) is satisfied is there.

yP <max (0, OffsetT) (H-3)
Here, the reason for the calculation of max is that when the upper end coordinate of the reference layer corresponding region SRLA is a negative value (when offsetT is a negative value), the correction is made to the upper end coordinate (0) of the resample reference layer picture rsPic. It is.

  (A4) When the lower end coordinate (yP + hPb-1) of the corresponding region is larger than the lower end coordinate (PH-OffsetB-1) of the reference layer corresponding region SRLA (RB4 in FIG. 6A), that is, The case where H-4) is satisfied.

yP + yPb-1> min (PH-1, PH-OffsetB-1) (H-4)
Here, the reason for the calculation of min is that the right end coordinate of the reference layer corresponding region SRLA is larger than the right end coordinate of the resample reference layer picture rsPic (if offsetR is a negative value), the right end of the resample reference layer picture rsPic This is to correct the coordinates (PW-1). Formula (H-4) can also be expressed as (H-4 ′).

yP + yPb> min (PH, PH-OffsetR) (H-4 ')
Note that max (A, B) is an operator that returns a larger value of A and B, and min (A, B) is an operator that returns a smaller value of A and B (the same applies hereinafter).

  That is, in the inter-layer image prediction, the corresponding region RBX on the resample reference layer picture rsPic corresponding to a certain prediction unit PBX on the target picture curPic satisfies any one of the above conditions (A1) to (A4) This indicates that an image outside the reference layer corresponding region SRLA is referred to.

(About inter-layer image prediction that refers only to images outside the reference layer corresponding region)
The inter-layer image prediction constraint flag described above uses inter-layer image prediction that refers to an image outside the reference layer corresponding region SRLA on the resample reference layer picture rsPic in all prediction units PBX on the target picture curPic. However, the present invention is not limited to this. For example, the inter-layer image prediction constraint flag prohibits the use of inter-layer image prediction that refers only to images outside the reference layer corresponding region SRLA on the sample reference layer picture rsPic in all prediction units PBX on the target picture curPic It may be defined as a flag to do. In the following, referring to FIG. 6B, in inter-layer image prediction, the corresponding region RBX on the resample reference layer picture rsPic corresponding to a certain prediction unit PBX on the target picture curPic is referred to from the reference layer corresponding region SRLA. A condition for referring to only the outer image will be described. In the figure, curPic represents a target picture, rlPic represents a reference layer picture, rsPic represents a resample reference layer picture, and SRLA represents a reference layer corresponding area. In the figure, the corresponding region on the resample reference layer picture rsPic corresponding to the prediction unit PBX (X = 1... 4) is RBX (X = 1... 4). The vertical width of the prediction unit PBX is hPb and the horizontal width wPb.

    (B1) When the right end coordinate (xP + wPb-1) of the corresponding region is smaller than the left end coordinate (offsetL) of the reference layer corresponding region SRLA (RB1 in FIG. 6B), that is, the following equation (H-5) This is the case.

xP + wPb-1 <max (0, OffsetL) (H-5)
(B2) When the left end coordinate (xP) of the corresponding region is larger than the right end coordinate (PW-OffsetR-1) of the reference layer corresponding region SRLA (RB3 in FIG. 6B), that is, the following equation (H-6) This is the case.

xP> min (PW-1, PW-OffsetR-1) (H-6)
(B3) When the lower end coordinate (yP + hPb-1) of the corresponding region is smaller than the upper end coordinate (offsetT) of the reference layer corresponding region SRLA (RB2 in FIG. 6B), that is, the following equation (H-7) This is the case.

yP + hPb-1 <max (0, OffsetT) (H-7)
(B4) When the upper end coordinate (yP) of the corresponding region is larger than the lower end coordinate (PH-OffsetB-1) of the reference layer corresponding region SRLA (RB4 in FIG. 6B), that is, the following equation (H-8) This is the case.

yP> min (PH-1, PH-OffsetB-1) (H-8)
The inter-layer image prediction constraint flag prohibits the use of inter-layer image prediction that refers only to images outside the reference layer corresponding region SRLA on the sample reference layer picture rsPic in all prediction units PBX on the target picture curPic. In the same way, since the inter-layer image prediction that refers only to the non-reference layer-corresponding NSRA pixels with low prediction accuracy is not used, an image decoding device and an image encoding device with higher encoding efficiency are similarly provided. It is possible to realize.

  In the picture parameter set PPS, a set of encoding parameters referred to by the hierarchical video decoding device 1 for decoding each picture in the target sequence is defined. For example, a reference value of a quantization width used for picture decoding and a flag indicating application of weighted prediction are included. A plurality of PPS may exist in the encoded data. In that case, one of a plurality of PPSs is selected from each picture in the target sequence. A PPS used for decoding a specific picture is also called an active PPS. Hereinafter, unless otherwise specified, PPS means an active PPS for the current picture.

(Picture layer)
In the picture layer, a set of data that is referred to by the hierarchical video decoding device 1 in order to decode a picture PICT to be processed (hereinafter also referred to as a target picture) is defined. The picture PICT includes slices S0 to SNS-1 as shown in FIG. (NS is the total number of slices included in picture PICT).

  Hereinafter, when it is not necessary to distinguish each of the slices S0 to SNS-1, the subscripts may be omitted. The same applies to other data with subscripts included in the hierarchically encoded data DATA described below.

(Slice layer)
In the slice layer, a set of data that is referred to by the hierarchical video decoding device 1 in order to decode a slice S to be processed (also referred to as a target slice) is defined. As shown in FIG. 2C, the slice S includes a slice header SH and slice data SDATA.

  The slice header SH includes an encoding parameter group that the hierarchical video decoding device 1 refers to in order to determine a decoding method of the target slice. Slice type designation information (slice_type) for designating a slice type is an example of an encoding parameter included in the slice header SH.

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

  The slice header SH includes a reference layer (active reference layer) that is actually referred to for inter-layer prediction in decoding / coding of the target picture among reference layers that can be referred to in the entire target sequence defined by the VPS. Active reference layer designation information inter_pred_enable_flag, num_inter_layer_ref_pics_minus1, inter_layer_pred_layer_idc [i] for designating (SYNSH01 on FIG. 7). The definition of each syntax is as follows.

  inter_layer_pred_enable_flag is a flag indicating the presence or absence of inter-layer prediction (also referred to as inter-layer prediction presence / absence flag) at the time of decoding the target picture curPic. When the value is 1, it indicates that inter-layer prediction is used, and the value is 0 In the case of, it indicates that inter-layer prediction is not used. If it is not explicitly included in the slice header SH, the value is estimated to be 0. Furthermore, when the value of the inter-layer prediction presence / absence flag is 1, num_inter_layer_ref_pic_minus1 and inter_layer_pred_layer_idc [i] are further included.

  num_inter_layer_ref_pic_minus1 + 1 represents the number of active reference layers (also referred to as the number of active reference layers) NumActiveRefLayerPics used for inter-layer prediction when decoding the current picture curPic. Specifically, based on the number of reference layers NumDirectRefLayers [curLayerId], the inter-layer prediction presence / absence flag inter_layer_pred_enable_flag and num_inter_layer_ref_pic_minus1, the number of active reference layers NumActiveRefLayerPics is derived, for example, by the following equation (G-9).

if (curLayerId == 0 || NumDirectRefLayers [curLayerId] == 0 ||
! inter_layer_pred_enable_flag) {
NumActiveRefLayerPics = 0;
} else {
NumActiveRefLayerPics = num_inter_layer_ref_pics_minus1 + 1;
} (G-9)
inter_layer_pred_layer_idc [i] represents the layer identifier of the i-th reference layer used for inter-layer prediction of the target picture curPic in the variable RefPicLayerId [i].

That is, RefPicLayerId [i] = RefLayerId [curLayerId] [inter_layer_pred_layer idc [i]];
In addition, the inter-active layer motion prediction reference layer number NumActivePredRefLayers and the inter-active layer motion reference layer ActiveMotionPredRefLayerId [i] are derived by, for example, the following equation (G-10).

for (i = 0, j = 0; NumActiveRefLayerPics; i ++)
RefPicLayerId [i] = RefLayerId [curLayerId] [inter_layer_pred_layer_idc [i]];
if (MotionPredEnableFlag [curLayerId] [inter_layer_pred_layer_idc [i]])
ActiveMotionPredRefLayerId [j ++] =
RefLayerId [curLayerId] [inter_layer_pred_layer_idc [i];
}
NumActiveMotionPredRefLayers = j; (G-10)
In addition, in the slice header SH, apart from the reference layer corresponding region information defined in SPS, an active reference layer corresponding region indicating which region on the target picture curPic of the target layer actually corresponds to the active reference layer picture Information (FIG. 7) may be included.

  The syntax active_scaled_ref_layer_offsets_param_present_flag is a flag indicating whether or not there is the target picture curPic of the target layer curLayerId and the number of active reference layers NumActiveRefLayerPics [curLayerId] active reference layer corresponding area information, separately from the reference layer corresponding area information defined in the SPS. Reference layer corresponding area information group presence / absence flag), if the value is true, it indicates that there are several reference layer corresponding area information for the active reference layer, and if the value is false, there is no active reference layer corresponding area information. Indicates. In the example of SYNSH02 in FIG. 7, when NumDirectRefLayers [curLyaerId] is greater than 0, an active reference layer corresponding region information group presence / absence flag is explicitly notified, and when NumDirectRefLayers [curLyaerId] is 0, active reference layer corresponding region information The group presence flag is estimated to be 0. Note that the conventional technology explicitly includes the syntax num_scaled_ref_layer_offsets that indicates how many reference layer corresponding region information exist even though the number of reference layers NumDirectRefLayers [curLayer] of the target layer is known. It was. On the other hand, in the present invention, when the reference layer corresponding region information group presence / absence flag is true, the active reference layer corresponding region information (NumActiveRefLayers [curLyaerId] pieces of active reference layer corresponding region information) of each active reference layer is explicitly notified. It is a configuration. Accordingly, it is possible to reduce the amount of codes related to the active reference layer corresponding region information as compared with the conventional technique that notifies the syntax num_scaled_ref_layer_offsets indicating how many reference layer corresponding region information exists. When NumActiveRefLayers [curLyaerId] is 0, the flag of the loop part by NumActiveRefLayers [curLyaerId] is not encoded. However, in order to more clearly indicate that these flags are not encoded, the active reference layer corresponding region information group presence / absence flag may be estimated to be zero.

  Instead of SYNSH02 in FIG. 7, the structure of SYNSH02A shown in FIG. That is, when NumActiveRefLayers [curLyaerId] is greater than 1, an active reference layer corresponding region information group presence / absence flag is explicitly notified. When NumActiveRefLayers [curLyaerId] is 0, the active reference layer corresponding region information group presence / absence flag is 0. When NumActiveRefLayers [curLyaerId] is 1, it is estimated that the active reference layer corresponding region information presence / absence flag is 1. Accordingly, when the number of active reference layers is one as compared with the example of SYNSH02 in FIG. 7, it is not necessary to explicitly notify the active reference layer corresponding region information group presence / absence flag, and the active reference layer corresponding region information group It is possible to reduce the code amount related to the presence / absence flag. Moreover, it is good also as a structure of SYNSH02B shown in FIG.34 (b). In this case, the active reference layer corresponding region information group presence / absence flag is not included, and NumActiveRefLayers [curLayer] pieces of active reference layer corresponding region information are explicitly notified. Similarly, it is possible to reduce the amount of codes related to the active reference layer corresponding region information as compared with the conventional technique that notifies the syntax num_scaled_ref_layer_offsets indicating how many reference layer corresponding region information exists.

  The syntax active_scaled_ref_layer_offset_present_flag [k] is a flag indicating whether or not there is active reference layer corresponding region information between the target layer curLayerId and the active reference layer RefPicLayerId [k] (referred to as active reference layer corresponding region information presence / absence flag), and the value is true. In this case, the following four syntaxes active_scaled_ref_layer_left_offset [k], active_scaled_ref_layer_top_offset [k], active_scaled_ref_layer_right_offset [k], and active_scaled_ref_layer_bottom_offset [k] are explicitly included as active reference layer corresponding region information. Each of the four syntax values is estimated to be zero. The definition of each syntax is as follows.

  active_scaled_ref_layer_left_offset [k] is a predetermined value between the upper left pixel of the active reference layer corresponding region SRLA 'on the resampled kth active reference layer RefPicLayerId [k] and the upper left pixel of the target picture curPic used for inter-layer prediction. This is an offset in the horizontal direction (x direction) in pixel units.

  active_scaled_ref_layer_top_offset [k] is a predetermined value between the upper left pixel of the active reference layer corresponding region SRLA ′ on the resampled kth active reference layer RefPicLayerId [k] and the upper left pixel of the target picture curPic used for inter-layer prediction. This is an offset in the vertical direction (y direction) in pixel units.

  active_scaled_ref_layer_right_offset [k] is the lowermost right pixel of the active reference layer corresponding region SRLA 'on the resampled kth active reference layer RefPicLayerId [k] and the lowermost right luminance pixel of the target picture curPic used for inter-layer prediction It is an offset in the horizontal direction (x direction) of a predetermined pixel unit between them.

  active_scaled_ref_layer_bottom_offset [k] is used for the inter-layer prediction, between the lowermost right pixel of the active reference layer corresponding region SRLA 'on the resampled kth reference layer RefPicLayerId [k] and the lowermost right pixel of the target picture curPic This is an offset in the vertical direction (y direction) in predetermined pixel units.

  Therefore, when the active reference layer corresponding region information presence / absence flag is 0, the code amount according to each syntax (active_scaled_ref_layer_left_offset [i], active_scaled_ref_layer_top_offset [i], active_scaled_ref_layer_right_offset [i], active_scaled_ref_layer_bottom_offset [i]) can be reduced. is there.

  The respective offsets OffsetL, OffsetT, OffsetR, and OffsetB in FIG. 4 are the syntaxes active_scaled_ref_layer_offset_present_flag [k], active_scaled_ref_layer_left_offset [k], active_scaled_off_layer_offset [k], active reference layer corresponding region information between the target layer curLayerId and the active reference layer RefPicLayerId [k]. [k], active_scaled_ref_layer_right_offset [k], and active_scaled_ref_layer_bottom_offset [k] are used to derive, for example, the following equations (G-1A) to (G-4A).

OffsetL = active_scaled_ref_layer_left_offset [k] <<sample_unit_bit; (G-1A)
OffsetT = active_scaled_ref_layer_top_offset [k] <<sample_unit_bit; (G-2A)
OffsetR = active_scaled_ref_layer_right_offset [k] <<sample_unit_bit; (G-3A)
OffsetB = active_scaled_ref_layer_bottom_offset [k] <<sample_unit_bit; (G-4A)
Conversely, each syntax active_scaled_ref_layer_left_offset [k], active_scaled_ref_layer_top_offset [k], active_scaled_ref_layer_right_offset [k], active_scaled_ref_layer_bottom_offset [k] is the inverse of expressions (G-1) to (G-4) In -4), it is derived in the same way by replacing the left side with the corresponding syntax. Also, the syntax active_scaled_ref_layer_offset_present_flag [k] is set for each syntax active_scaled_ref_layer_left_offset [k], active_scaled_ref_layer_top_offset [k], active_scaled_ref_layer_right_offset [k], active_scaled_ref_layer_bottom_offset is set to 0, and all values are 0. In this case, it is set to 1.

  That is, when active reference layer corresponding region information is notified in the slice header SH, each offset OffsetL, OffsetT, OffsetR, and OffsetB determined by the reference layer corresponding region information notified on the SPS is the active reference layer corresponding region information. It is reset based on. The advantage of notifying active reference layer corresponding area information in units of slices is that more accurate reference layer corresponding area information is notified for sequences in which the corresponding areas of the target layer and the reference layer change in units of pictures. It becomes possible, and more accurate inter-layer motion mapping and inter-layer image mapping can be performed. Accordingly, the accuracy of inter-layer motion mapping and inter-layer image mapping is improved, and accordingly, the prediction accuracy of inter-layer motion prediction and inter-layer image prediction is also improved, so that it is possible to improve the coding efficiency. .

  Further, the data structure of the active reference layer corresponding area information is not limited to SYNA05 in FIG. 7, and may be difference information (SYNSH03 in FIG. 8) with respect to the reference layer corresponding area information notified by the SPS. Hereinafter, the definition of the syntax of SYNSH03 in FIG. 8 will be described with reference to FIG. The active reference layer corresponding region information group presence flag and the active reference layer corresponding region presence / absence flag are omitted because they have already been described. In FIG. 9, a corresponding region (reference layer corresponding region) between the target layer image and the reference layer image will be described. RlPic in the figure is a reference layer image (reference layer picture) having an image size of vertical width RLPH and horizontal width RLPW. An rsPic in the figure is an image (resampled reference layer picture) rsPic obtained by mapping the reference layer picture rlPic to an image of a target layer having an image size of the vertical width PH and the horizontal width PW. SRLA in the figure is an area (reference layer corresponding area) that actually corresponds to the image of the reference layer on the target layer image determined by the reference layer corresponding area information notified by SPS. It has a size of horizontal width SRLPH. OffsetL in the drawing represents an offset in the horizontal direction (x direction) between the upper left pixel of the reference layer corresponding region SRLA and the upper left pixel of the resample reference picture rsPic (or the target picture curPic of the target layer). OffsetT in the drawing represents an offset in the vertical direction (y direction) between the upper left pixel of the reference layer corresponding region SRLA and the upper left pixel of the resample reference picture rsPic (or the target picture curPic of the target layer). OffsetR in the figure represents an offset in the horizontal direction (x direction) between the lowermost right pixel of the reference layer corresponding region SRLA and the lowermost right pixel of the resample reference picture rsPic (or the target picture curPic of the target layer). . OffsetB in the figure represents an offset in the vertical direction (y direction) between the lowermost right pixel of the reference layer corresponding area SRLA and the lowermost right pixel of the resample reference picture rsPic (or the target picture curPic of the target layer). . SRLA 'in the figure is an area (active reference layer corresponding area) actually corresponding to the reference layer image on the target layer image determined by the active reference layer corresponding area information notified by the slice header SH. , The vertical width SRLPH ′ and the horizontal width SRLPH ′. OffsetT 'in the figure is an offset in the vertical direction (y direction) between the upper left pixel of the active reference layer corresponding region SRLA' and the upper left pixel of the resample reference picture rsPic (or the target picture curPic of the target layer). Represent. OffsetR ′ in the figure is the horizontal direction (x direction) between the lowermost right pixel of the active reference layer corresponding region SRLA ′ and the lowermost right pixel of the resample reference picture rsPic (or the target picture curPic of the target layer). Represents an offset. OffsetB 'in the figure is the vertical direction (y direction) between the lowermost right pixel of the active reference layer corresponding region SRLA' and the lowermost right pixel of the resample reference picture rsPic (or the target picture curPic of the target layer). Represents an offset. ΔL in the figure represents the difference between the offsets OffsetL and OffsetL ′, ΔT represents the difference between the offsets OffsetT and OffsetT ′, ΔR represents the difference between the offsets OffsetR and OffsetR ′, and ΔB represents the offset OffsetB And the difference between OffsetB '.

  active_diff_scaled_ref_layer_left_offset [k] is an offset in the horizontal direction (x direction) in a predetermined pixel unit between the upper left pixel of the reference layer corresponding region SRLA and the upper left pixel of the active reference layer corresponding region SRLA ′.

  active_diff_scaled_ref_layer_top_offset [k] is an offset in the vertical direction (y direction) in a predetermined pixel unit between the upper left pixel of the reference layer corresponding region SRLA and the upper left pixel of the active reference layer corresponding region SRLA ′.

  active_diff_scaled_ref_layer_left_offset [k] is an offset in the horizontal direction (x direction) in a predetermined pixel unit between the lowermost right pixel of the reference layer corresponding region SRLA and the lowermost right pixel of the active reference layer corresponding region SRLA ′.

active_diff_scaled_ref_layer_bottom_offset [k] is an offset in the vertical direction (y direction) in a predetermined pixel unit between the lowermost right pixel of the reference layer corresponding region SRLA and the lowermost right pixel of the active reference layer corresponding region SRLA ′.
If the above four syntaxes are not explicitly included on the slice header SH, the value of each syntax is assumed to be zero.

  Therefore, when the reference layer corresponding region information is not necessary in the reference layer i, the active reference layer corresponding region information presence / absence flag is set to 0 to set each syntax (active_diff_scaled_ref_layer_left_offset [i], active_diff_scaled_ref_layer_top_offset [i], active_diff_scaled_ref_layer_right_offset [i] , Active_diff_scaled_ref_layer_bottom_offset [i]) can be reduced.

  In SYNSH03 of FIG. 8, when the number of active reference layers NumActiveRefLayerPics [curLayerId] is greater than 0, the active reference layer corresponding region information presence / absence flag is explicitly notified, and when the number of active reference layers NumActiveRefLayerPics [curLayerId] is 0, The active reference layer corresponding region information presence / absence flag is estimated to be zero. Instead of SYNSH03 in FIG. 8, the structure of SYNSH03B shown in FIG. That is, when NumActiveRefLayers [curLyaerId] is greater than 1, an active reference layer corresponding region information group presence / absence flag is explicitly notified. When NumActiveRefLayers [curLyaerId] is 0, the active reference layer corresponding region information group presence / absence flag is 0. When NumActiveRefLayers [curLyaerId] is 1, it is estimated that the active reference layer corresponding region information presence / absence flag is 1. This eliminates the need to explicitly notify the active reference layer corresponding region information group presence / absence flag when the number of active reference layers is one, compared to the example of SYNSH03 in FIG. It is possible to reduce the code amount related to the presence / absence flag. Moreover, it is good also as a structure of SYNSH03B shown in FIG.35 (b). In this case, the active reference layer corresponding region information group presence / absence flag is not included, and NumActiveRefLayers [curLayer] pieces of active reference layer corresponding region information are explicitly notified. Similarly, it is possible to reduce the amount of codes related to the active reference layer corresponding region information as compared with the conventional technique that notifies the syntax num_scaled_ref_layer_offsets indicating how many reference layer corresponding region information exists.

  Each offset OffsetL ', OffsetT', OffsetR ', and OffsetB' of the active reference layer corresponding region SRLA 'in FIG. 9 is active with each offset OffsetL, OffsetT, OffsetR, OffsetB of the reference layer corresponding region SRLA and the target layer curLayerId. Active reference layer corresponding region information between the reference layers RefPicLayerId [k] active_scaled_ref_layer_offset_present_flag [k], active_diff_scaled_ref_layer_left_offset [k], active_diff_scaled_ref_layer_top_offset [k], active_diff_scaled_ref_layer_ref_layer_ref_layer_off_k (G-1B) to (G-4B).

OffsetL '= OffsetL + active_diff_scaled_ref_layer_left_offset [k] <<sample_unit_bit; (G-1B)
OffsetT '= OffsetT + active_diff_scaled_ref_layer_top_offset [k] <<sample_unit_bit; (G-2B)
OffsetR '= OffsetR + active_diff_scaled_ref_layer_right_offset [k] <<sample_unit_bit; (G-3B)
OffsetB '= OffsetB + active_diff_scaled_ref_layer_bottom_offset [k] <<sample_unit_bit; (G-4B)
Conversely, each syntax active_diff_scaled_ref_layer_left_offset [k], active_diff_scaled_ref_layer_top_offset [k], active_diff_scaled_ref_layer_right_offset [k], active_scaled_ref_layer_bottom_offset [k] is the inverse of expressions (G-1B) to (G-4B) It is derived by (I-4B).

active_diff_scaled_ref_layer_left_offset [k] = (OffsetL '-OffsetL) >>sample_unit_bit; (I-1B)
active_diff_scaled_ref_layer_top_offset [k] = (OffsetT '-OffsetT) >>sample_unit_bit; (I-2B)
active_diff_scaled_ref_layer_right_offset [k] = (OffsetR '-OffsetR) >>sample_unit_bit; (I-3B)
active_diff_scaled_ref_layer_bottom_offset [k] = (OffsetB '-OffsetB) >>sample_unit_bit; (I-4B)
Note that the value of active_scaled_ref_layer_offset_present_flag [k] is set to 0 when the values of each syntax derived by the formulas (I-1B) to (I-4B) are all 0, otherwise Is determined by setting it to 1.

  Also, the horizontal width SRLPW 'and the vertical width SRLPH' of the active reference layer corresponding region SRLA 'in FIG. 9 are derived by, for example, the following equations (G-5A) to (G-6A).

SRLPW '= PW-OffsetL'-OffsetR '; (G-5A)
SRLPH '= PH-OffsetT'-OffsetB '; (G-6A)
In addition, the horizontal size ratio ScaleFactorX and the vertical size ratio ScaleFactorY of the active reference layer corresponding region SRLA ′ and the reference layer picture rlPic in FIG. 9 are the SRLPW in the above-described equations (G-7) to (G-8). Is replaced with SRLPW 'and SRLPH is replaced with SRLPH'.

  As described above, the active reference layer corresponding area information is notified as difference information with respect to the reference layer corresponding area information notified by the SPS, compared to the data structure of SYNA05 in FIG. 7 that explicitly notifies the size of the active reference layer corresponding area. As a result, there is an effect of reducing the amount of code necessary to notify the size of the active reference layer corresponding area. Hereinafter, unless otherwise specified, the reference layer corresponding region SRLA and the active reference layer region SRLA ′ are simply referred to as the reference layer corresponding region SRLA without being distinguished from each other. The active reference layer corresponding area information (reference layer corresponding area in units of pictures) may be notified once in the first slice of each picture. This has the effect of reducing the amount of code necessary for notifying active reference layer corresponding region information compared with the case of notifying in units of slices constituting each picture.

  Further, when the slice type is a P slice or a B slice, collocated information collocated_from_l0_flag, collocated_ref_idx, alt_collocated_indication_flag, and collocated_ref_layer_idex for specifying temporal motion information described later is included.

Note that the slice header SH may include a PPS identifier (pic_parameter_set_id) indicating a reference to the picture parameter set PPS included in the sequence layer.
In addition, in the parameter set such as the slice header SH, the spatial scalability, temporal scalability, and SNR scalability, view scalability hierarchy identification information (dependency_id, temporal_id, quality_id, and view_id, respectively) of the target layer are encoded. May be.

(Slice data layer)
In the slice data layer, a set of data referred to by the hierarchical video decoding device 1 for decoding the slice data SDATA to be processed is defined. The slice data SDATA includes a coding tree unit (CTU) as shown in (d) of FIG. The coding tree unit CTU is an image area having a fixed size (for example, 64 × 64 pixels) that constitutes a slice. An image block corresponding to the coding tree unit CTU is referred to as a coding tree block (CTB).

(Encoding tree layer)
As shown in FIG. 2E, the coding tree layer defines a set of data that the hierarchical video decoding device 1 refers to in order to decode the coding tree unit to be processed. The coding tree unit is divided by recursive quadtree division. A tree structure obtained by recursive quadtree partitioning is called a coding tree. The coding tree unit CTU includes a split flag (split_flag). When the split_flag is 1, the coding tree unit CTU is further divided into four CTUs. When split_flag is 0, the coding tree unit CTU is divided into four coding units (CU: Coding Unit). The coding unit CU is a terminal node of the coding tree layer and is not further divided in this layer. The encoding unit CU is a basic unit of encoding / decoding processing.

  When the size of the encoding tree unit CTU is 64 × 64 pixels, the size of the encoding unit CU is 64 × 64 pixels, 32 × 32 pixels, 16 × 16 pixels, or 8 × 8 pixels. It can take. Note that an image block corresponding to the coding unit CU is referred to as a coding block (CB).

(Encoding unit layer)
As shown in (f) of FIG. 2, the encoding unit layer defines a set of data that the hierarchical video decoding device 1 refers to in order to decode the processing target encoding unit. Specifically, the encoding unit is a prediction tree composed of a CU header CUH, one or more prediction units (PU: Prediction Unit), and a transform composed of one or more transform units (TU: Transform Unit). Consists of a tree.

  In the CU header CUH, prediction type information PType indicating whether the encoding unit is a unit using intra prediction or a unit using inter prediction is defined.

  In the prediction tree, the encoding unit CU is divided into one or a plurality of prediction units PU, and the position and size of each prediction unit are defined. Broadly speaking, there are two types of division in the prediction tree: intra prediction and inter prediction. Intra prediction is prediction within the same picture, and inter prediction refers to prediction processing performed between different pictures (for example, between display times and between layer images).

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

In the case of inter prediction, the division method is defined by the division mode (part_mode) included in the CU header CUH. If the size of the target CU is 2N × 2N, there are the following eight patterns in total. That is, 2N × 2N (same size as coding unit), 2N × N, N × 2N and N × N symmetric splitting, and 2N × nU, 2N × nD, N × 2N , NL × 2N, and nR × 2N, there are four asymmetric splitting. N = 2 ^m (m is an arbitrary integer of 1 or more). Hereinafter, a prediction unit obtained by dividing the target CU is referred to as a prediction block or a partition. Since the number of divisions is one of 1, 2, and 4, PUs included in the CU are 1 to 4. These PUs are expressed as PU0, PU1, PU2, and PU3 in order.

  In the conversion tree, the encoding unit CU is divided into one or a plurality of conversion units TU, and the position and size of each conversion unit are defined. There are two types of division in the conversion tree: one in which an area having the same size as the encoding unit is allocated as a conversion unit, and the other in division by recursive quadtree division, similar to the above-described division in the encoding tree block.

  Note that the image blocks corresponding to the prediction unit PU and the transform unit TU are referred to as a prediction block (PB: Prediction Block) and a transform block (TB: Transform Block), respectively.

(Prediction parameter)
The prediction image of the prediction unit is derived by a prediction parameter associated with the prediction unit. The prediction parameters include a prediction parameter for intra prediction or a prediction parameter for inter prediction. Hereinafter, prediction parameters for inter prediction (inter prediction parameters) will be described. The inter prediction parameter includes prediction list use flags predFlagL0 and predFlagL1, reference picture indexes refIdxL0 and refIdxL1, and vectors mvL0 and mvL1. The prediction list use flags predFlagL0 and predFlagL1 are flags indicating whether or not reference picture lists called L0 list and L1 list are used, respectively. When the value is 1, the reference picture list corresponding to each flag is used. . In this specification, when “flag indicating whether or not XX” is described, it is assumed that the value is XX when the value is 1, and that it is not XX when the value is 0. In products and the like, 1 is treated as true and 0 is treated as false (the same applies hereinafter). However, other values can be used as true values and false values in an actual apparatus or method. When two reference picture lists are used, that is, when predFlagL0 = 1 and predFlagL1 = 1, the prediction method is called bi-prediction, and when one reference picture list is used, that is, (predFlagL0, predFlagL1) = (1, 0) or (predFlagL0, predFlagL1) = (0,1), the prediction method is called single prediction. Note that the prediction list use flag information can also be expressed by an inter prediction identifier inter_pred_idc described later.

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

  In addition, as a prediction parameter, information for specifying inter-layer image prediction may be included in distinction between intra prediction and inter prediction. For example, a flag (interlayer image prediction flag) that specifies whether or not to apply inter-layer image prediction is included. Note that the inter-layer image prediction flag may be referred to as texture_rl_fla.

  Further, in the hierarchically encoded data, the encoded data of the enhancement layer may be generated by a different encoding method from the lower layer encoding method. That is, the encoding / decoding process of the enhancement layer does not depend on the type of the lower layer codec. The lower layer may be encoded by, for example, MPEG-2 or H.264 / AVC format.

  Note that the parameters described above may be encoded independently, or a plurality of parameters may be encoded in combination. When a plurality of parameters are encoded in combination, an index is assigned to the combination of parameter values, and the assigned index is encoded. Also, if the parameter can be derived from another parameter or decoded information, the encoding of the parameter can be omitted.

(Example of reference picture list)
Next, an example of the reference picture list will be described. The reference picture list is a column composed of reference pictures stored in a reference picture memory 306 (FIG. 13) described later. FIG. 10A is a conceptual diagram illustrating an example of a reference picture list. In the reference picture list 601, five rectangles arranged in a line on the left and right indicate reference pictures, respectively. Reference symbols P0, P1, Q2, P3, and P4 shown in order from the left end to the right are symbols indicating respective reference pictures. P such as P1 indicates a layer P, and Q of Q2 indicates a layer Q different from the layer P. The subscripts P and Q indicate a picture order number POC (Picture Order Count). A downward arrow directly below refIdxLX indicates that the reference picture index refIdxLX is an index that refers to the reference picture Q2 in the reference picture memory 306.

(Reference picture example)
Next, an example of a reference picture used for deriving a vector will be described. FIG. 11 is a conceptual diagram illustrating an example of a reference picture. In FIG. 11, the horizontal axis represents the display time, and the vertical axis represents the number of layers. The illustrated rectangles in 2 rows and 3 columns (6 in total) indicate pictures. Among the six rectangles, the rectangle in the second column from the left in the lower row indicates a picture to be decoded (target picture), and the remaining five rectangles indicate reference pictures. A reference picture Q2 indicated by a downward arrow from the target picture is a picture having the same display time as that of the target picture and having a different layer. In inter-layer prediction based on the target picture curPic (P2), the reference picture Q2 is used. A reference picture P1 indicated by a left-pointing arrow from the target picture is the same layer as the target picture and is a past picture. A reference picture P3 indicated by a rightward arrow from the target picture is the same layer as the target picture and is a future picture. In motion prediction based on the target picture, the reference picture P1 or P3 is used.

(Inter prediction flag and prediction list usage flag)
The relationship between the inter prediction identifier and the prediction list use flags predFlagL0 and predFlagL1 can be mutually converted as follows. Therefore, as an inter prediction parameter, a prediction list use flag may be used, or an inter prediction identifier may be used. In addition, hereinafter, the determination using the prediction list use flag may be replaced with the inter prediction identifier. Conversely, the determination using the inter prediction identifier inter_pred_idc can be replaced with a prediction list use flag.

inter_pred_idc = (predFlagL1 << 1) + predFlagL0;
predFlagL0 = inter_pred_idc &1;
predFlagL1 = inter_pred_idc >>1;
Here, >> is a right shift, and << is a left shift.

(Merge prediction and AMVP prediction)
The prediction parameter decoding (encoding) method includes a merge prediction (merge) mode and an AMVP (Adaptive Motion Vector Prediction) mode. The merge flag merge_flag is a flag for identifying these. In both the merge prediction mode and the AMVP mode, the prediction parameter of the target PU is derived using the prediction parameter of the already processed block. The merge prediction mode is a mode in which the prediction parameter already used is used as it is without including the prediction list use flag predFlagLX (inter prediction identifier inter_pred_idc), the reference picture index refIdxLX, and the vector mvLX in the encoded data. In this mode, the prediction identifier inter_pred_idc, the reference picture index refIdxLX, and the vector mvLX are included in the encoded data. The vector mvLX is encoded as a prediction vector index (mvp_LX_idx) indicating a prediction vector and a difference vector (mvdLX).

  The inter prediction identifier inter_pred_idc is data indicating the type and number of reference pictures, and takes any value of Pred_L0, Pred_L1, and Pred_Bi. Pred_L0 and Pred_L1 indicate that reference pictures stored in reference picture lists called an L0 list and an L1 list are used, respectively, and that both use one reference picture (single prediction). Prediction using the L0 list and the L1 list are referred to as L0 prediction and L1 prediction, respectively. Pred_Bi indicates that two reference pictures are used (bi-prediction), and indicates that two reference pictures stored in the L0 list and the L1 list are used. The prediction vector index mvp_LX_idx is an index indicating a prediction vector, and the reference picture index refIdxLX is an index indicating a reference picture stored in the reference picture list. Note that LX is a description method used when L0 prediction and L1 prediction are not distinguished. By replacing LX with L0 and L1, parameters for the L0 list and parameters for the L1 list are distinguished. For example, refIdxL0 is a reference picture index used for L0 prediction, refIdxL1 is a reference picture index used for L1 prediction, and refIdx (or refIdxLX) is a notation used when refIdxL0 and refIdxL1 are not distinguished.

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

(Motion vector and displacement vector)
The vector mvLX includes a motion vector and a displacement vector. A motion vector is a positional shift between the position of a block in a picture at a certain display time of a layer and the position of the corresponding block in a picture of the same layer at a different display time (for example, an adjacent discrete time). It is a vector to show. The displacement vector is a vector indicating a positional shift between the position of a block in a picture at a certain display time of a certain layer and the position of a corresponding block in a picture of a different layer at the same display time. As pictures of different layers, there are cases where the pictures are of different resolution (spatial scalability), pictures of different quality (SNR scalability), pictures of different viewpoints (view scalability), and the like. In the following description, when a motion vector and a displacement vector are not distinguished, they are simply referred to as a vector mvLX. A prediction vector and a difference vector related to the vector mvLX are referred to as a prediction vector mvpLX and a difference vector mvdLX, respectively. Whether the vector mvLX and the difference vector mvdLX are motion vectors or displacement vectors is distinguished using a reference picture index refIdxLX attached to the vector.

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

(Configuration of Hierarchical Video Decoding Device)
The schematic configuration of the hierarchical video decoding device 1 will be described with reference to FIG. FIG. 12 is a functional block diagram showing a schematic configuration of the hierarchical video decoding device 1. The hierarchical video decoding device 1 decodes the hierarchical encoded data DATA supplied from the hierarchical video encoding device 2 to generate a target layer decoded image POUT # T. In the following description, it is assumed that the target layer is an enhancement layer. Therefore, the target layer is also an upper layer with respect to the reference layer. Conversely, the reference layer is also a lower layer with respect to the target layer.

    As illustrated in FIG. 12, the hierarchical video decoding device 1 includes a NAL demultiplexing unit 11, a target layer picture decoding unit 12, and a reference layer picture decoding unit 13.

  The NAL demultiplexing unit 11 demultiplexes hierarchically encoded data DATA transmitted in units of NAL units in NAL (Network Abstraction Layer).

  The NAL is a layer provided to abstract communication between a VCL (Video Coding Layer) and a lower system that transmits and stores encoded data.

  VCL is a layer that performs moving image encoding processing, and encoding is performed in VCL. On the other hand, the lower system here corresponds to the H.264 / AVC and HEVC file formats and the MPEG-2 system.

  In NAL, a bit stream generated by VCL is divided into units called NAL units and transmitted to a destination lower system. The NAL unit includes encoded data encoded by the VCL and a header for appropriately delivering the encoded data to the destination lower system. Also, the encoded data in each layer is stored in the NAL unit, is NAL multiplexed, and is transmitted to the hierarchical moving image decoding apparatus 1.

  The NAL demultiplexing unit 11 demultiplexes the hierarchical encoded data DATA, and extracts the target layer encoded data DATA # T and the reference layer encoded data DATA # R. Further, the NAL demultiplexing unit 11 supplies the target layer encoded data DATA # T to the target layer picture decoding unit 12 and also supplies the reference layer encoded data DATA # R to the reference layer picture decoding unit 13.

  The target layer picture decoding unit 12 decodes the target layer decoded picture from the target layer encoded data DATA # T and the reference layer decoded picture. Details of the target layer picture decoding unit 12 will be described later.

  The reference layer picture decoding unit 13 decodes a reference layer decoded picture from the reference layer encoded data DATA # R. The reference layer decoded picture is a decoded picture of the reference layer used when decoding the decoded picture of the target layer. The reference layer picture decoding unit 13 supplies the decoded reference layer decoded picture to the target layer picture decoding unit 12. The reference layer picture decoding unit 13 has a function equivalent to that of the target layer picture decoding unit 12, and thus detailed description thereof is omitted.

  Details of the target layer picture decoding unit 12 will be described below.

(Target layer picture decoding unit 12 (image decoding device))
The detailed configuration of the target layer picture decoding unit 12 will be described with reference to FIG. FIG. 13 is a functional block diagram illustrating the configuration of the target layer picture decoding unit 12. The target layer picture decoding unit 12 includes a variable length decoding unit 301, a prediction parameter decoding unit 302, a reference picture memory (reference picture storage unit, frame memory) 306, a prediction parameter memory (prediction parameter storage unit, frame memory) 307, a prediction image A generation unit 308, an inverse quantization / inverse DCT unit 311, an addition unit 312, and a resampling unit 314 are configured. Note that if the target layer is a base layer, the resampling unit 314 is not necessary.

  The prediction parameter decoding unit 302 includes an inter prediction parameter decoding unit 303, an intra prediction parameter decoding unit 304, and an inter-layer information deriving unit 320 (not shown). The predicted image generation unit 308 includes an inter predicted image generation unit 309 and an intra predicted image generation unit 310. The resampling unit 314 includes an inter-layer image mapping unit 315 and an inter-layer motion mapping unit 316.

  The variable length decoding unit 301 performs variable length decoding on target layer encoded data DATA # T input from the outside, and separates and decodes individual codes (syntax elements). The separated codes include prediction information for generating a prediction image and residual information for generating a difference image.

  The variable length decoding unit 301 outputs a part of the separated code to the prediction parameter decoding unit 302. Some of the separated codes are, for example, prediction mode predMode, split mode part_mode, merge flag merge_flag, merge index merge_idx, inter prediction flag inter_pred_idc, reference picture index refIdxLX, prediction vector index mvp_LX_idx, difference vector mvdLX, number of layers vps_max_layers_minus1 ( SYNVPS01 in FIG. 3), layer identifier designation information (SYNVPS02 in FIG. 3), reference layer designation information (SYNVPS04 in FIG. 3), layer dependent type information (SYNVPS05 in FIG. 3), reference layer corresponding area information (FIG. 5), inter-layer image prediction constraint flag (SYNSPS03 in FIG. 5), active reference layer designation information (SYNSH01 in FIG. 7), active reference layer corresponding region information (SYNSH02 in FIG. 7), collocated information collocated_from_l0_flag Collocated_ref_idx, alt_collocated_indication_flag, collocated_ref_layer_idex, etc. Control of which code to decode is performed based on an instruction from the prediction parameter decoding unit 302. The variable length decoding unit 301 outputs the quantized coefficient to the inverse quantization / inverse DCT unit 311. This quantization coefficient is a coefficient obtained by performing quantization and performing DCT (Discrete Cosine Transform) on the residual signal in the encoding process.

  The prediction parameter decoding unit 302 decodes the inter prediction parameter or the intra prediction parameter based on the code input from the variable length decoding unit 301. The decoded prediction parameter is output to the prediction image generation unit 308 and stored in the prediction parameter memory 307. The prediction parameter decoding unit 302 also extracts collocated information collocated_from_l0_flag, collocated_ref_idx, alt_collocated_indication_flag, and collocated_ref_layer_idex for designating temporal motion information, and stores them in the prediction parameter memory 307.

  The inter prediction parameter decoding unit 303 refers to the prediction parameters stored in the prediction parameter memory 307 and outputs inter prediction parameters. Details of the inter prediction parameter decoding unit 303 will be described later.

  The intra prediction parameter decoding unit 304 decodes the intra prediction parameter with reference to the prediction parameter stored in the prediction parameter memory 307 based on the code input from the variable length decoding unit 301. The intra prediction parameter is a parameter used in a process of predicting a picture block within one picture, for example, an intra prediction mode IntraPredMode. The intra prediction parameter decoding unit 304 outputs the decoded intra prediction parameter to the prediction image generation unit 308 and stores it in the prediction parameter memory 307.

  The inter-layer information deriving unit 320 uses the reference layer corresponding region SRLA on the resampled reference layer picture rsPic as an inter-layer correspondence parameter for the reference layer j referenced by the target layer i based on the decoded reference layer corresponding region information. The offsets OffsetL, OffsetT, OffsetR, and OffsetB that indicate the positions of the reference layer corresponding to the reference layer corresponding region SRLA and the vertical width SRLPH are derived using the above equations (G-1) to (G-4). Derived using G-5) to (G-6).

  Subsequently, if there is active reference layer corresponding area information corresponding to the reference layer j referred to by the target layer i, the offsets OffsetL, OffsetT, OffsetR, OffsetB indicating the position of the reference layer corresponding area SRLA using the information, and the reference The horizontal width SRLPW and vertical width SRLPH of the layer corresponding area SRLA are reset.

(When using SYNSH02 in Fig. 7)
When SYNSH02 of FIG. 7 is used as the active reference layer corresponding region information, the offsets OffsetL, OffsetT, OffsetR, and OffsetB are derived by the above formulas (G-1A) to (G-4A), and the reference layer corresponding region SRLA The horizontal width SRLPW and the vertical width SRLPH are derived by the above-described equations (G-5) to (G-6).

(When using SYNSH03 in Fig. 8)
When SYNSH03 in FIG. 8 is used as the active reference layer corresponding region information, difference values ΔL, ΔT, ΔR, and ΔB (FIG. 9) are respectively obtained for the derived offsets OffsetL, OffsetT, OffsetR, and OffsetB. Addition is performed to derive offsets OffsetL ′, OffsetT ′, OffsetR ′, and OffsetB ′ (corresponding to the equations (G-1B) to (G-4B) described above). after that,
The horizontal width SRLPW ′ and the vertical width SRLPH ′ of the active reference layer corresponding region SRLA ′ are derived by the above-described equations (G-5A) to (G-6A).

  Subsequently, the horizontal width size ratio ScaleFactorX and the vertical width size ratio ScaleFactorY of the reference layer corresponding region SRLA and the reference layer picture rlPic are derived using the above-described equations (G-7) to (G-8).

  Inter-layer correspondence parameters (OffsetL, OffsetT, OffsetR, OffsetB, SRLPW, SRLPH, ScaleFactorX, ScaleFactorY, etc.) derived by the inter-layer information deriving unit 3020 are stored in the prediction parameter memory 307.

  The reference picture memory 306 stores a reference picture block (reference picture block) generated by an adder 312 described later at a predetermined position for each picture and block to be decoded.

  The prediction parameter memory 307 stores the prediction parameter at a predetermined position for each picture and block to be decoded. Specifically, the prediction parameter memory 307 stores the inter prediction parameter decoded by the inter prediction parameter decoding unit 303, the intra prediction parameter decoded by the intra prediction parameter decoding unit 304, and the prediction mode predMode separated by the variable length decoding unit 301. To do. The stored inter prediction parameters include, for example, a prediction list utilization flag predFlagLX (inter prediction identifier inter_pred_idc), a reference picture index refIdxLX, and a vector mvLX.

  The prediction image generation unit 308 receives the prediction mode predMode input from the variable length decoding unit 301 and the prediction parameter from the prediction parameter decoding unit 302. Further, the predicted image generation unit 308 reads a reference picture from the reference picture memory 306. The predicted image generation unit 308 generates a predicted picture block P (predicted image) using the input prediction parameter and the read reference picture according to the prediction mode indicated by the prediction mode predMode.

  Here, when the prediction mode predMode indicates the inter prediction mode, the inter prediction image generation unit 309 uses the inter prediction parameter input from the inter prediction parameter decoding unit 303 and the read reference picture to perform the prediction picture block P by inter prediction. Is generated. The predicted picture block P corresponds to the PU. The PU corresponds to a part of a picture composed of a plurality of pixels as a unit for performing the prediction process as described above, that is, a decoding target block on which the prediction process is performed at once.

  For the reference picture list (L0 list or L1 list) for which the prediction list use flag predFlagLX is 1, the inter predicted image generation unit 309 generates a vector mvLX based on the decoding target block from the reference picture indicated by the reference picture index refIdxLX. The reference picture block at the position indicated by is read from the reference picture memory 306. The inter prediction image generation unit 309 performs prediction on the read reference picture block to generate a prediction picture block P. The inter prediction image generation unit 309 outputs the generated prediction picture block P to the addition unit 312.

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

  The intra predicted image generation unit 310 generates a predicted picture block by performing prediction in the prediction mode indicated by the intra prediction mode IntraPredMode for the read reference picture block. The intra predicted image generation unit 310 outputs the generated predicted picture block P to the addition unit 312.

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

  The adder 312 outputs the prediction picture block P input from the inter prediction image generation unit 309 and the intra prediction image generation unit 310 and the signal value of the decoded residual signal input from the inverse quantization / inverse DCT unit 311 for each pixel. Addition to generate a reference picture block. The adder 312 stores the generated reference picture block in the reference picture memory 306, and outputs the target layer decoded picture POUT # T in which the generated reference picture block is integrated for each picture to the outside.

  The resampling unit 314 includes the reference layer corresponding region information, the inter-layer image prediction constraint flag, and the active reference layer corresponding region information recorded in the prediction parameter memory 307, and the reference layer decoded picture decoded by the reference layer picture decoding unit 15. Using the motion information rlPicMotion (referred to as the reference layer picture rlPic) and the image rlPicSample, the resample motion information rsPicMotion and the resampled image rsPicSample of the resample reference layer picture rsPic are respectively inter-layer motion mapping unit 316 and inter-layer image mapping. Generated in part 315. The generated resample motion information rsPicMotion is stored in the prediction parameter memory 307. The generated resample image rsPicSample is stored in the reference picture memory 306. Details of the inter-layer image mapping unit 315 and the inter-layer motion mapping unit 316 will be described later.

(Configuration of inter prediction parameter decoding unit)
Next, the configuration of the inter prediction parameter decoding unit 303 will be described. FIG. 14_ is a schematic diagram illustrating a configuration of the inter prediction parameter decoding unit 303 according to the present embodiment. The inter prediction parameter decoding unit 303 includes an inter prediction parameter decoding control unit 3031, an AMVP prediction parameter derivation unit 3032, an addition unit 3035, and a merge prediction parameter derivation unit 3036.

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

  The inter prediction parameter decoding control unit 3031 first extracts a merge flag merge_flag. Hereinafter, when expressing that the inter prediction parameter decoding control unit 3031 extracts a syntax element, the variable length decoding unit 301 is instructed to decode a certain syntax element, and the corresponding syntax element is read from the encoded data. Means that. Here, when the value indicated by the merge flag is 1, that is, indicates the merge prediction mode, the inter prediction parameter decoding control unit 3031 extracts the merge index merge_idx as a prediction parameter related to merge prediction. The inter prediction parameter decoding control unit 3031 outputs the extracted merge index merge_idx to the merge prediction parameter derivation unit 3036.

  When the merge flag merge_flag is 0, that is, indicates the AMVP prediction mode, the inter prediction parameter decoding control unit 3031 extracts the AMVP prediction parameter. As an AMVP prediction parameter, for example, there are an inter prediction identifier inter_pred_idc, a reference picture index refIdxLX, a vector index mvp_LX_idx, and a difference vector mvdLX. The inter prediction parameter decoding control unit 3031 outputs the prediction list use flag predFlagLX derived from the extracted inter prediction identifier inter_pred_idc and the reference picture index refIdxLX to the AMVP prediction parameter derivation unit 3032 and the prediction image generation unit 308 (FIG. 13). Moreover, it memorize | stores in the prediction parameter memory 307 (FIG. 13). The inter prediction parameter decoding control unit 3031 outputs the extracted vector index mvp_LX_idx to the AMVP prediction parameter deriving unit 3032 (motion information deriving unit). The inter prediction parameter decoding control unit 3031 outputs the extracted difference vector mvdLX to the addition unit 3035.

  FIG. 15 is a schematic diagram illustrating a configuration of the merge prediction parameter deriving unit 3036 (motion information deriving unit) according to the present embodiment. The merge prediction parameter derivation unit 3036 includes a merge candidate derivation unit 30361 and a merge candidate selection unit 30362. The merge candidate derivation unit 30361 includes a merge candidate storage unit 303611 and a basic merge candidate derivation unit 303613.

  The merge candidate storage unit 303611 stores the merge candidate input from the basic merge candidate derivation unit 303613. The merge candidate includes a prediction list use flag predFlagLX, a vector mvLX, and a reference picture index refIdxLX.

  The basic merge candidate derivation unit 303613 includes a spatial merge candidate derivation unit 3036131, a temporal merge candidate derivation unit 3036132, a merge merge candidate derivation unit 3036133, and a zero merge candidate derivation unit 3036134.

  The spatial merge candidate derivation unit 3036131 reads the prediction parameters (prediction list use flag predFlagLX, vector mvLX, reference picture index refIdxLX) stored in the prediction parameter memory 307 according to a predetermined rule, and uses the read prediction parameters as merge candidates. To derive. The prediction parameter to be read is a prediction parameter relating to each of the blocks within a predetermined range from the decoding target block (for example, all or a part of the blocks in contact with the lower left end, upper left upper end, and upper right end of the decoding target block, respectively). is there. The derived merge candidates are stored in the merge candidate storage unit 303611.

  The temporal merge candidate derivation unit 3036132 predicts motion information of the reference picture colPic specified by collocated information collocated_from_l0_flag, collocated_ref_idx, alt_collocated_indication_flag, and collocated_ref_layer_idx in the slice header of the slice including the decoding target block. By referring to the parameter memory 307, motion information called a time merge candidate is derived. When the value of alt_collocated_indication_flag is 0, temporal merge candidate motion information is derived based on the motion information of the reference picture colPic on the same layer specified by collocated_from_l0_flag and collocated_ref_idx. On the other hand, when the value of alt_collocated_indication_flag is 1, based on the resampled motion information rsPicMotion resampled by the inter-layer motion mapping 315, the motion information of the reference layer picture rlPic specified by collocated_ref_layer_idx is used as the motion information of the temporal merge candidate. To derive.

  A prediction parameter of a block in the reference picture colPic including the lower right coordinate BR of the decoding target block is read from the prediction parameter memory 307 and set as a merge candidate. The method of deriving the reference picture colPic and the lower right coordinate BR is the same as the method of the time vector candidate deriving unit 303322, and will be described later. Note that the motion information referenced by the temporal merge candidate derivation unit 3036132 and the temporal vector candidate derivation unit 303322 is referred to as temporal motion information. The derived merge candidates are stored in the merge candidate storage unit 303611.

  FIG. 16 shows an example of the positional relationship of a block (a block including coordinates A0, A1, B0, B1, and B2) from which a prediction parameter is read out when a spatial merge candidate is derived with respect to the decoding target block X. In addition, regarding the decoding target block X, an example of the positional relationship of the blocks (blocks including the coordinate BR) in the reference picture colPic that is a target for referring to the prediction parameter (motion information) when the temporal merge candidate is derived is shown. The block Y in the figure is a block in the reference picture colPic at a position corresponding to the decoding target block X. Regarding the relationship between these block positions, the block position from which the prediction parameter is read when the vector candidate is derived in the space vector candidate deriving unit 303321 described later and the vector candidate in the time vector candidate deriving unit 303322 are derived. Similarly, the block positions targeted for reference to the prediction parameters (motion information) have the same relationship.

  The merge merge candidate derivation unit 3036133 derives merge merge candidates by combining two different derived merge candidate vectors and reference picture indexes already derived and stored in the merge candidate storage unit 303611 as L0 and L1 vectors, respectively. To do. The derived merge candidates are stored in the merge candidate storage unit 303611.

  The zero merge candidate derivation unit 3036134 derives a merge candidate in which the reference picture index refIdxLX is 0 and both the X component and the Y component of the vector mvLX are 0. The derived merge candidates are stored in the merge candidate storage unit 303611.

  The merge candidate selection unit 30362 selects, from the merge candidates stored in the merge candidate storage unit 303611, a merge candidate to which an index corresponding to the merge index merge_idx input from the inter prediction parameter decoding control unit 3031 is assigned. As an inter prediction parameter. The merge candidate selection unit 30362 stores the selected merge candidate in the prediction parameter memory 307 (FIG. 13) and outputs it to the prediction image generation unit 308 (FIG. 13).

  FIG. 17 is a schematic diagram illustrating the configuration of the AMVP prediction parameter deriving unit 3032 according to the present embodiment. The AMVP prediction parameter derivation unit 3032 includes a vector candidate derivation unit 3033 and a prediction vector selection unit 3034.

  The vector candidate derivation unit 3033 reads a vector (motion vector or displacement vector) stored in the prediction parameter memory 307 (FIG. 13) as a vector candidate mvpLX based on the reference picture index refIdx, and derives a predetermined number of vector candidates. Store in the vector candidate storage unit 30331. The derived vector is determined by a space vector candidate derivation unit 303321, a time vector candidate derivation unit 303322, and a zero vector candidate derivation unit 303323.

  The space vector candidate derivation unit 303321 is a vector related to each of the blocks within a predetermined range from the decoding target block (for example, all or a part of the blocks touching the lower left end, the upper left end, and the upper right end of the decoding target block). Are read out from the prediction parameter memory and set as vector candidates.

  The time vector candidate derivation unit 303322 predicts the motion information of the reference picture colPic specified by the collocated information collocated_from_l0_flag, collocated_ref_idx, alt_collocated_indication_flag, and collocated_ref_layer_idx for specifying temporal motion information in the slice header of the slice including the decoding target block By referring to the parameter memory 307, motion information called a time vector candidate is derived. A vector related to the block in the reference picture including the lower right coordinate of the decoding target block is read from the prediction parameter memory 307 and set as a vector candidate. When the value of alt_collocated_indication_flag is 0, the motion information of the time vector candidate is derived based on the motion information of the reference picture colPic on the same layer specified by collocated_from_l0_flag and collocated_ref_idx. On the other hand, when the value of alt_collocated_indication_flag is 1, based on the resampled motion information rsPicMotion resampled by the inter-layer motion mapping 315, the motion information rlPicMotion of the reference layer picture rlPic specified by collocated_ref_layer_idx is motion information of temporal motion vector candidates. Is derived.

  A method for deriving the reference picture colPic and the lower right coordinate BR will be described below. When the inter-layer motion prediction flag alt_collocated_indication_flag is equal to 1, the resampled reference layer picture rsPic of the active reference layer ActiveMotionPredRefLayerId [collocated_ref_layer_idx] specified by the collocated reference layer index collocated_ref_layer_idx in the same access unit as the target picture is the target of temporal motion information The reference picture colPic is When the inter-layer motion prediction flag alt_collocated_indication_flag is equal to 0, the reference picture colPic is derived as follows. When the slice type of the slice including the decoding target block is B slice and the collocated information collocated_from_l0_flag is equal to 0, the reference picture (= RefPicList1 [collocated_ref_idx]) at the position indicated by the temporal index collocated_ref_idx in the reference picture list L1 The reference picture colPic is the target of temporal motion information. On the other hand, even when the slice type is B slice, the above condition is not satisfied, or when the slice type is P slice, the reference picture (= RefPicList0 [collocated_ref_idx]) at the position indicated by the index collocated_ref_idx in the reference picture list L0 is selected. The reference picture colPic is the target of temporal motion information.

  For the lower right coordinates BR, when the coordinates of the decoding target block are (xPb, yPb) and the size is (nPbW, nPbH), the lower right coordinates xColBr and yColBr of the block are derived by the following equations (see FIG. 16).

xColBr = xPb + nPbW
yColBr = yPb + nPbH
Further, the coordinates are generated by the following formula so that the horizontal component and the vertical component of the coordinate are each a multiple of 16.

xColBr´ = ((xColBr >> 4) << 4
yColBr´ = ((yColBr >> 4) << 4
The coordinates (xColBr ′, yColBr ′) after the generation are set as the lower right coordinates BR indicating the reference position of the temporal motion information.

  The zero vector candidate derivation unit 303323 generates a zero vector whose horizontal component and vertical component are both zero as a vector candidate. The generation of the zero vector is executed only when the number of vector candidates derived by the space vector candidate deriving unit and the time vector candidate deriving unit does not reach the predetermined number. For example, when a block in a range that is a target of a space vector candidate or a block that is a target of a temporal vector candidate is subjected to intra prediction encoding, there is no motion vector related to the block, and thus it cannot be used as a vector candidate. As a result, when the number of vector candidates is less than the predetermined number, the zero vector candidate derivation unit generates a zero vector and outputs it to the vector candidate storage unit. The vector candidate storage unit 30331 stores the candidate vectors output from the space vector candidate derivation unit 303321, the time vector candidate derivation unit 303322, and the zero vector candidate derivation unit 303323 in order to a predetermined number in the prediction vector list. Here, the predetermined number regarding the vector candidates is, for example, 2, and the vector candidate deriving unit 3033 may derive each vector candidate until the predetermined number is reached, and the subsequent derivation processing may be omitted.

  The prediction vector selection unit 3034 selects, as the prediction vector mvpLX, a vector candidate indicated by the vector index mvp_LX_idx input from the inter prediction parameter decoding control unit 3031 among the vector candidates read by the vector candidate derivation unit 3033. The prediction vector selection unit 3034 outputs the selected prediction vector mvpLX to the addition unit 3035.

  The candidate vector is a block for which decoding processing has been completed, and is generated based on a vector related to the referenced block with reference to a block (for example, an adjacent block) in a predetermined range from the decoding target block. The adjacent block has a block that is spatially adjacent to the target block, for example, the left block and the upper block, and a block that is temporally adjacent to the target block, for example, the same position as the target block, and has a different display time. Contains blocks derived from blocks. Regarding candidate vectors, in order to distinguish between a case where a reference block is a block spatially adjacent to a decoding target block and a case where it is a temporally adjacent block, a spatial motion vector and a temporal motion vector (or (Temporal motion vector, temporal motion information).

  The addition unit 3035 adds the prediction vector mvpLX input from the prediction vector selection unit 3034, that is, the AMVP prediction parameter derivation unit 3032, and the difference vector mvdLX input from the inter prediction parameter decoding control unit 3031 to calculate a vector mvLX. The adding unit 3035 outputs the calculated vector mvLX to the predicted image generation unit 308 (FIG. 13).

(Inter-layer image mapping part)
Next, the configuration of the inter-layer image mapping unit 315 will be described. The inter-layer image mapping unit 315 generates a resample image rsPicSample of the resample reference layer picture rsPic from the image rlPicSample of the reference layer picture rlPic by inter-layer image mapping.

  FIG. 18 shows the configuration of the inter-layer image mapping unit 315. The inter-layer image mapping unit 315 includes a reference pixel deriving unit 3151 for deriving the position of the reference pixel in the reference layer picture rlPic corresponding to each pixel of the resample reference layer picture rsPic, the pixel at the derived position and its surroundings It further includes a resample image generation unit 3152 that applies a resample filter to the pixels to generate a resample image.

  The inter-layer image mapping unit 315 has a luminance in the range of xP = 0 ... PW-1, yP = 0 ... PH-1) on the resample reference layer picture rsPic, and xPC = 0 ... PWC-1 and yPC = 0. ... generate pixel values of color difference in the range of PHC-1). Here, PWC and PHC are the horizontal width and vertical width in the color difference of the resample reference layer picture rsPic, respectively. When the inter-layer image prediction constraint flag inter_pred_sample_constraint_flag is true, the reference layer corresponding region SRLA (luminance (xP = offsetL ... PW-offsetR-1, yP = offsetT ... PH-offsetB-1), color difference (xPC = 0ffsetL / 2 ... PWC-offsetR / 2-1, offsetT / 2 ... PHC-offset / 2-1) Only the images in the range are referenced in the inter-layer image prediction. You may memorize | store in the picture memory 308. FIG. As a result, it is possible to simplify the process of generating the resampled image (brightness, color difference) of the NSRL outside the reference layer corresponding area, and to reduce the memory for holding it.

The reference pixel position deriving unit 3151 uses the inter-layer correspondence parameters (OffsetL, OffsetT, OffsetR, OffsetB, SRLPW, SRLPH, ScaleFactorX, ScaleFactorY) derived by the inter-layer information deriving unit 3020 to resample the reference layer picture rsPic The position of the reference pixel on the reference layer picture rlPic corresponding to each upper pixel is calculated. Specifically, when the coordinates of the target pixel in the picture are (xP, yP), the reference pixel position (xRef, yRef) and the phase (xPhase, yPhase) are derived by the following procedure, and the resampled image generation unit 3152 is output.
(1) The reference pixel position (xRefMP, yRefMP) with 1/2 ^ MP pixel accuracy (MP is an integer up to 0... Nosf_bit) is derived by, for example, equations (N-1) to (N-2). For example, if the precision is 1/16 pixel, MP = 4.

xRefMP = (((xP-offsetX) * ScaleFactorX +
(1 << (nosf_bit-MP-1)) >>(nosf_bit-MP)); (N-1)
yRefMP = (((yP-offsetY) * ScaleFactorY +
(1 << (nosf_bit-MP-1)) >>(nosf_bit-MP)); (N-2)
Here, offsetX and offsetY have different values depending on luminance and color difference. In the case of luminance, offsetX = OffsetL and offsetY = offsetT. In the case of a color difference, offsetX = OffsetL / 2 and offsetY = offsetT / 2. The derivation of the reference pixel position (xRefMP, yRefMP) with 1/2 ^ MP pixel accuracy is not limited to the equations (N-1) to (N-2). For example, considering the sample positions of luminance and color difference, in the case of luminance, the equations (N-1) to (N-2), and in the case of color difference, the equations (N-1A) to (N-2A), (N- 1B) to (N-2B) may be derived. Here, phaseX and phaseY are phase differences at the sample position of the color difference with respect to the luminance.

(In the case of color difference)
xRefMP = (((xP-offsetX) * ScaleFactorX + iAddX)
>> (nosf_bit-MP))-(phaseX <<2); (N-1A)
iAddX = (((RLPW * phaseX) << (nosf_bit -2)) + (SRLPW >> 1)) / SRLPW +
+ (1 <<(nosf_bit-1));(N-1B);
yRefMP = (((yP-offset) * ScaleFactorY + iAddY)
>> (nosf_bit-MP))-(phaseY <<2); (N-2A)
iAddY = (((RLPH * phaseY) << (nosf_bit -2)) + (SRLPH >> 1)) / SRLPH
+ (1 <<(nosf_bit-1)); (N-2B)
(2) From the derived reference pixel position of 1/2 ^ MP pixel precision (xRefMP, yRefMP), the integer precision reference pixel position value (xRef, yRef) and phase (xPhase, yPhase) Derived from (N-6).

xRef = (xRefMP >>MP); (N-3)
xPhase = (xRefMP% (1 <<MP)); (N-4)
yRef = (yRefMP >>MP); (N-5)
yPhase = (yRefMP% (1 <<MP)); (N-6)
The resample image generation unit 3152 applies the derived reference pixel position (xRef, yRef) and phase (xPhase, yPhase) and a predetermined resample filter to generate and generate a resample pixel intSample of luminance and color difference The resampled image rsPicSample is stored in the reference picture memory 308.

(In case of luminance)
First, the range (filter area) of the horizontal position xPosRL (xPosRL = xRef-fs / 2 +1 ... xRef + fs / 2) on the reference layer picture rlPic and the vertical position yPosRL (yPosRL = yRef-1 ... yRef + fs-1) ) Is applied to a pixel rlPicSampleL at a predetermined resampling filter FL (e.g., an 8-tap, 1 / 16-pixel precision filter shown in FIG. 19), and a pixel tempArray [n] (n = 0... Fs −1). ) Is generated (formula (N-7)). Here, Expression (N-7) represents that the resample filter is applied in the horizontal direction. Note that fs represents the number of filter taps.

tempArray [n] =
ΣFL [xPhase, i] * rlPicSampleL [Clip3 (0, RLPW-1, xRef-fs / 2 + 1 + i), yPosRL]; (N-7)
Here, Clip3 (a, b, X) is such that a ≦ X ≦ b with respect to X by setting X = a when X <a and X = b when b <X. A function that limits X. That is, in the above equation, Clip 3 (0, RLPW-1, xRef-fs / 2 + 1 + i) is the horizontal reference pixel position (xRef-fs / 2 + 1 + i) to which the resample filter is applied. ) Indicates coordinates outside the screen, it indicates an operation for correcting to the screen end coordinates. I takes a value of 0... Fs−1. Further, when yPosRL indicates coordinates outside the screen of the reference layer picture rlPic, it is corrected to the screen edge coordinates by the following equation (N-8).

yPosRL = Clip3 (0, RLPH-1, yRef + n-1); (N-8)
Subsequently, a predetermined resample filter FL (for example, an 8-tap, 1 / 16-pixel precision filter shown in FIG. 19) is applied to the derived pixel tempArray [n] (n = 0... Fs−1). Then, the value rsPicSampleL [xP] [yP] of the target pixel (xP, yP) is derived (expressions (N-9) to (N-10)). Here, Expression (N-9) represents that the resample filter is applied in the vertical direction.

intSample = ((ΣFL [yPhase, i] * tempArray [i]) + (1 << 11)) >>12; (N-9)
rsPicSampleL [xP] [yP] = Clip3 (0, (1 << BitDepthY), intSample); (N-10)
Here, i takes a value of 0... Fs−1, and BitDepthY represents the bit precision of luminance.

(In the case of color difference)
First, the horizontal position xPosRL (xPosRL = xRef-fs / 2 + 1 ... xRef + fs / 2) on the reference layer picture rlPic and the vertical position yPosRL (yPosRL = yRef- fs / 2 + 1 ... yRef + fs / 2) A predetermined resample filter FC (for example, a 4-tap, 1 / 16-pixel precision filter shown in FIG. 20) is applied to the pixel rlPicSampleC in the range (filter region), and the pixel tempArray [n] (n = 0 ... fs-1) is generated (formula (N-11)).

tempArray [n] =
ΣFC [xPhase, i] * rlPicSampleC [Clip3 (0, RLPWC-1, xRef-1 + i), yPosRL]; (N-11)
Here, i takes a value of 0... Fs−1. Further, when yPosRL indicates coordinates outside the screen of the reference layer picture rlPic, it is corrected to the screen edge coordinates by the following equation (N-12).

yPosRL = Clip3 (0, RLPHC-1, yRef + n-1); (N-12)
Here, RLPWC and RLPHC are the lateral width and lateral width of the color difference of the reference layer picture rlPic, respectively.

  Subsequently, a predetermined resample filter FC (for example, a 4-tap, 1/16 pixel precision filter shown in FIG. 20) is applied to the derived pixel tempArray [n] (n = 0... Fs−1). Then, the value rsPicSampleC [xP] [yP] of the target pixel (xP, yP) is derived (expressions (N-12) to (N-13)).

intSample = ((ΣFC [yPhase, i] * tempArray [i]) + (1 << 11)) >>12; (N-12)
rsPicSampleC [xP] [yP] = Clip3 (0, (1 << BitDepthC), intSample); (N-13)
Here, i takes a value of 0... Fs−1, and BitDepthC represents the bit accuracy of the color difference.

  Note that the inter-layer image mapping unit 315 identifies the reference layer picture rlPic by any of the following methods, and performs inter-layer image mapping based on the inter-layer correspondence parameter.

  (Reference layer picture specifying method 1) An active reference layer specified by active reference layer specification information (SYNSH01 in FIG. 7) on a slice header is set as a reference layer picture rlPic that is a target of inter-layer image mapping. That is, when the inter-layer prediction presence / absence flag is true (1), the number of active reference layers (num_inter_layer_ref_pic_minus1 + 1) active reference layers (RefLayerId [curLayerId] [inter_layer_pred_idc]) is a target of inter-layer image mapping.

  (Reference layer picture specifying method 2) Among the reference pictures included in the reference picture list, when the layer ID of the reference picture is different from the layer ID of the decoding target image, the reference layer that is the target of inter-layer image mapping Let it be a picture. Specifically, the layer IDs of the reference pictures in RefPicList0 [] and RefPicList1 [] are scanned, and a reference picture different from the layer ID of the decoding target image is specified.

  As described above, in the inter-layer image mapping unit 315, the inter-layer correspondence parameters (OffsetL, OffsetT, OffsetR, OffsetB, SRLPW, SRLPH, and the like between the target layer (for example, the enhancement layer) and the reference layer (for example, the base layer) Based on ScaleFactorX, ScaleFactorY, etc.), the position of the reference pixel on the reference layer picture rlPic corresponding to each pixel on the resample reference layer picture rsPic is determined, and a predetermined resample filter is applied to the reference pixel and surrounding pixels Thus, the target pixel can be generated. Thereby, the effect which improves the precision of the resample image used by the image prediction between layers can be acquired. In particular, for a sequence in which the corresponding region of the target layer and the reference layer changes in units of pictures, compared to the case of performing inter-layer image mapping based on the inter-layer correspondence parameter derived from the reference layer corresponding region information, The accuracy of the resampled image used in inter-layer image prediction by performing inter-layer image mapping based on the inter-layer correspondence parameter derived from the active reference layer corresponding region information (reference layer corresponding region information for each picture) The effect which improves more is produced. As a result, the prediction accuracy of inter-layer image prediction is also improved, so that the encoding efficiency can be improved.

(Operation of image mapping between layers in the present invention)
A resample pixel generation process related to coordinates (xP, yP) on the resample reference layer picture rsPic in the inter-layer image mapping unit according to the present invention will be described with reference to FIG. FIG. 29 is a flowchart showing the operation of the resample pixel generation process for the coordinates (xP, yP) on the resample reference layer picture rsPic in the inter-layer image mapping unit according to the present invention.

  (Step S802) The reference pixel position deriving unit 3151 determines the reference pixel position (xRefMP, yRefMP) with 1/2 ^ MP pixel accuracy corresponding to each coordinate (xP, yP) from the above-described formulas (N-1) to (N Derived by -2).

  (Step S803) The reference pixel position deriving unit 3151 calculates the reference pixel position (xRef, yRef) and phase (xPhase, yPhase) with integer pixel precision from the derived reference pixel position with 1/2 ^ MP pixel precision using the above-described formula Derived from (N-3) to (N-6).

  (Step S804) The resampled image generation unit 3152, the horizontal position xPosRL (xPosRL = xRef−fs / 2 + 1... XRef + fs / 2) on the reference layer picture rlPic, the vertical position yPosRL (yPosRL = yRef-1... YRef + fs-1) Apply a predetermined resample filter to the pixel rlPicSampleX (X = L, C) in the range (filter area), and set the pixel tempArray [n] (n = 0 ... fs-1) (Formula (N-7) or (N-12)).

  (Step S805) The resample image generation unit 3152 applies a predetermined resample filter to the derived pixel tempArray [n] (n = 0... Fs−1), and the value of the target pixel (xP, yP). rsPicSampleX [xP] [yP] (X = L, C) is derived (formulas (N-9) to (N-10) or (N-12) to (N-13)).

(Operation of the inter-layer image mapping unit in the prior art)
On the other hand, resampled pixel generation processing related to coordinates (xP, yP) on the resample reference layer picture rsPic in the inter-layer image mapping unit in the prior art will be described with reference to FIG. FIG. 30 is a flowchart showing the operation of the resample pixel generation process for the coordinates (xP, yP) on the resample reference layer picture rsPic in the inter-layer image mapping unit in the prior art.

  (Step S801 ′) The reference pixel position deriving unit 3151 in the prior art has a luminance in the range of xP = 0... PW-1, yP = 0... PH−1 on the resample reference layer picture rsPic, and xPC = 0. PWC-1, yPC = 0 ... When generating each pixel of color difference in the range of PHC-1, first, the coordinates (xP ', yP') where the coordinates (xP, yP) are limited within the reference layer corresponding area SRLA ) Is derived based on equations (N-20) to (N-21). That is, as shown in FIG. 31 (a), when the coordinate (xP, yP) on the resample reference layer picture rsPic is outside the reference layer corresponding region SRLA, the reference layer correspondence closest to the coordinate (xP, yP) This is a process of replacing the coordinates (xP ′, yP ′) of the boundary pixels of the region SRLA.

xP '= Clip3 (offsetL, PW-offsetR-1, xP); (N-20)
yP '= Clip3 (offsetT, PH-offsetB-1, yP); (N-21)
(Step S802 ′) The reference pixel position deriving unit 3151 in the prior art calculates the reference pixel position (xRefMP, yRefMP) of 1/2 ^ MP pixel accuracy corresponding to the derived coordinates (xP ′, yP ′) using the above-described formula ( N-1) to (N-2).

  (Step S803) The reference pixel position deriving unit 3151 in the related art calculates the reference pixel position (xRef, yRef) and phase (xPhase, yPhase) with integer pixel precision from the derived reference pixel position with 1/2 ^ MP pixel precision. It is derived from the above formulas (N-3) to (N-6).

  (Step S804) The resampled image generation unit 3152 in the related art uses the horizontal position xPosRL (xPosRL = xRef−fs / 2 + 1... XRef + fs / 2) on the reference layer picture rlPic, the vertical position yPosRL (yPosRL = yRef− 1… yRef + fs-1) Apply a predetermined resampling filter to pixel rlPicSampleX (X = L, C) in the range to generate pixel tempArray [n] (n = 0 ... fs-1) (Formula (N-7) or (N-12)).

  (Step S805) The resample image generation unit 3152 in the prior art applies a predetermined resample filter to the derived pixel tempArray [n] (n = 0... Fs−1), and the target pixel (xP, yP ) Value rsPicSampleX [xP] [yP] (X = L, C) is derived (expressions (N-9) to (N-10) or (N-12) to (N-13)).

(Effect of the inter-layer image mapping unit of the present invention)
Hereinafter, differences between the prior art and the present invention will be described, and effects of the inter-layer image mapping unit of the present invention will be described. As shown in FIG. 31 (a), the difference between the prior art and the present invention is that when the coordinates (xP, yP) on the resample reference layer picture rsPic are outside the reference layer corresponding region SRLA, the coordinates (xP , yP) is the presence / absence of a process of replacing the nearest reference layer corresponding region SRLA with the coordinates (xP ′, yP ′) of the boundary pixels (step S801 ′ in FIG. 30). As a result, as shown in FIG. 32 (a), the pixel (xP, yP) outside the reference layer corresponding region NSRLA on the resample reference layer picture rsPic in the prior art is the closest boundary on the reference layer corresponding region SRLA. This is the same as the pixel (xP ′, yP ′).

  On the other hand, in the present invention, as shown in FIG. 31 (b), when the coordinates (xP, yP) on the resample reference layer picture rsPic are outside the reference layer corresponding region SRLA, they are directly on the reference layer picture rlPic. A reference pixel position (xRef, yRef) is derived. Therefore, it is possible to simplify the derivation process related to the derivation of the reference pixel position as compared with the conventional technique.

  In the present invention, the pixel (xP, yP) outside the reference layer corresponding region NSRLA on the resample reference layer picture rsPic is the closest pixel of the boundary pixel (xP ′, yP ′) on the reference layer corresponding region SRLA. And not necessarily the same. Specifically, in FIG. 32B, regarding the region NSRLA ′ (NSRLA ′ on FIG. 32B) having a width ΔFX and a height ΔFY in the horizontal direction outside the boundary of the reference layer corresponding region SRLA, The pixel value changes smoothly, and the pixels outside the region NSRLA ′ are the same as the border pixels of the closest pixel region NSRLA ′. Here, the sizes of ΔFX and ΔFY are, for example, the number of taps (filter size) fs of the resample filter and the width of the reference layer corresponding region SRLA as shown in the equations (N-22) to (N-24). It is determined by SRLPW, vertical width SRLPH, and horizontal width RLPW and vertical width RLPH of reference layer picture rlPic.

ΔFX = (fs * ScaleFactorXA + (1 << (nosf_bit-1)) >>(nosf_bit)); (N-22)
ΔFY = (fs * ScaleFactorYA + (1 << (nosf_bit-1)) >>(nosf_bit)); (N-23)
ScaleFactorXA = ((SRLPW << nosf_bit) + (RLPW >> 1)) / RLPW; (N-24)
ScaleFactorYA = ((SRLPH << nosf_bit) + (RLPH >> 1)) / RLPH; (N-24)
Note that ScaleFactorXA is the size ratio of the horizontal width SRLPW of the reference layer corresponding region SRLA to the horizontal width RLPW of the reference layer picture rlPic, and ScaleFactorYA is also the size ratio of the vertical width SRLPH of SRLA to the vertical width of rsPic. For example, the size of the reference layer corresponding area SRLA is 1920x1080 (SRLPW = 1920, SRLPH = 1080), the size of the reference layer picture rlPic is 960x540 (RLPW = 960, RLPH = 540), filter size fs = 8, bit accuracy nosf_bit = 16 Then, ΔFX = 16 and ΔFY = 16 are derived as shown in the following equations, respectively.

ΔFX = (8 * (((1920 << 16) + (960 >> 1)) / 960) + (1 << 15)) >> 16 = 16;
ΔFY = (8 * (((1080 << 16) + (540 >> 1)) / 540) + (1 << 15)) >> 16 = 16;
Also, the size of the reference layer corresponding area SRLA is 1920x1080 (SRLPW = 1920, SRLPH = 1080), the size of the reference layer picture rlPic is 1280x720 (RLPW = 1280, RLPH = 720), filter size fs = 8, bit accuracy nosf_bit = 16 Then, ΔFX = 12, ΔFY = 12, respectively, as shown in the following equations.

ΔFX = (8 * (((1920 << 16) + (1280 >> 1)) / 1280) + (1 << 15)) >> 16 = 12;
ΔFX = (8 * (((1080 << 16) + (720 >> 1)) / 720) + (1 << 15)) >> 16 = 12;
Such a resampled image is generated because the pixel (xP, yP) on the NSRLA outside the reference layer corresponding region, for example, the vertical position yP is fixed and the horizontal position xP in the horizontal direction is xP = 0. When changing to offsetT-1, the filter area to which the resample filter is applied (with the reference pixel position (xRef, yRef) on the reference layer picture rsPic as the center, the horizontal position xPosRL (xPosRL = xRef-fs / 2 +1 ... xRef + fs / 2), vertical position yPosRL (yPosRL = yRef-1 ... yRef + fs-1) range, FLTA on Fig. 31 (b) is different from the conventional technology in the coordinates (xP, yP) This is because it changes accordingly. In the filter area FLTA, a pixel that refers to coordinates outside the screen of the reference layer picture rlPic is replaced with a pixel at the screen edge having a high correlation (close spatial distance) with the pixel.

  As described above, the inter-layer image mapping unit according to the present invention generates the resample pixel of each coordinate of the non-reference layer corresponding region NSRLA on the resample reference layer picture rsPic on the reference layer picture rsPic to which the resample filter is applied. In the filter area FLTA, if there is a pixel with coordinates outside the screen, a resampled image is generated using a pixel having a high correlation (close spatial distance) with that pixel. As a result, the accuracy of the resampled image of the NSRLA outside the reference layer corresponding region can be improved as compared with the conventional technique. In addition, with regard to inter-layer image prediction that refers to a pixel outside the reference layer corresponding region NSRLA, prediction accuracy can be improved as compared with the conventional technique. Therefore, the encoding efficiency is also improved. In particular, in the present invention, it is possible to generate a region where the pixel value of the resampled image changes smoothly in a region NSRLA ′ having a width ΔFX and a height ΔFY in the horizontal direction outside the boundary of the reference layer corresponding region SRLA. . Therefore, in the inter-layer image prediction, it is possible to improve the prediction accuracy of the inter-layer image prediction that refers to the region NSRLA ′ among the reference layer corresponding non-region NSRLA. The inter-layer image mapping unit in the present invention can be applied independently regardless of the inter-layer image prediction constraint flag.

(Inter-layer motion mapping unit)
Next, the configuration of the inter-layer motion mapping unit 316 will be described. The inter-layer motion mapping unit 316 generates resample motion information rsPicMotion of the resample reference layer picture rsPic and motion information rlPicMotion of the reference layer picture rlPic by motion mapping.

  FIG. 18 shows the configuration of the inter-layer motion mapping unit 316. The inter-layer motion mapping unit 315 is based on the reference image block deriving unit 3161 that determines a reference image block that is an image block in the reference layer corresponding to the target block in the target layer, and the motion information of the determined reference image block. It further includes a motion information generation unit 3162 that generates motion information of the target block.

  The reference image block deriving unit 3161 uses the inter-layer correspondence parameters (OffsetL, OffsetT, OffsetR, OffsetB, SRLPW, SRLPH, ScaleFactorX, ScaleFactorY) derived by the inter-layer information deriving unit 3020 to resample the reference layer picture rsPic The position of the reference image block on the reference layer picture rlPic corresponding to the predetermined unit target block (for example, 16 × 16) is calculated.

The target block is a block on the resample reference layer picture rsPic that is a target of motion mapping. The target block is also a block referred to as a temporary motion vector of the decoding target block on the target layer. Specifically, when the coordinates in the picture of the target block are (xP, yP), the coordinates (xRL, yRL) of the reference image block are derived by the following procedure.
(1) The center coordinates (xPCtr, yPCtr) of the target block are derived by equations (M-1) to (M-2).

xPCtr = xP + ctrOffsetX; (M-1)
yPCtr = yP + ctrOffsetY; (M-2)
Here, ctrOffsetX and ctrOffsetY are an offset in the horizontal direction (x direction) and an offset in the vertical direction (y direction) from the upper left pixel position of the target block to the center pixel position of the target block, respectively. If the size of the target block is 2 ^ M1 × 2 ^ N1 (M1 and N1 are natural numbers), that is, width 2 ^ M1 and height 2 ^ N1, ctrOffsetX = 2 ^ (M1-1), ctrOffsetY = 2 ^ It is preferable to set (N1-1). For example, if the size of the target block is 16 × 16, the value of each offset is 8.
(2) The coordinates (xRef, yRef) on the reference layer picture rlPic corresponding to the derived center coordinates (xPCtr, yPCtr) of the target block are derived by the equations (M-3) to (M-4).

xRef =
((xPCtr-OffsetL) * ScaleFactorX + (1 << (nosf_bit-1))) >>nosf_bit; (M-3)
yRef =
((yPCtr-OffsetT) * ScaleFactorX + (1 << (nosf_bit-1))) >>nosf_bit; (M-4)
(3) The coordinates (xRL, yRL) of the reference image block are derived by equations (M-5) to (M-6).

xRL = (xRef >> M2) <<M2; (M-5)
yRL = (yRef >> N2) <<N2; (M-6)
Here, M2 and N2 are values representing the size 2 ^ M2 × 2 ^ N2 of the reference image block, respectively. For example, if the size of the reference image block is 16 × 16, M2 = 4 and N2 = 4. Note that the recording unit of motion information is preferably the same for the reference layer picture rlPic and the resample reference layer picture rsPic.

  The reference image block deriving unit 3131 outputs the derived position of the reference image block to the motion information generating unit 3132.

  The motion information generation unit 3132 refers to the motion information rlPicMotion of the reference layer picture rlPic corresponding to the coordinates (xRL, yRL) of the reference image block input from the reference image block derivation unit 3131, and based on this, the resample reference layer Resample motion information rsPicMotion (prediction parameter of the target block referred to as a temporary motion vector of the decoding target block) of the target block on the picture rsPic is generated. Specifically, for the motion information (prediction mode predMode, reference picture index refIdxLX, vector mvLX) of the target block, a predetermined value is set according to conditions described later, and the generated motion information (rsPicMotion) is used as the prediction parameter memory 307. To remember.

  When generating each prediction parameter, the motion information generation unit 3132 determines the prediction parameter as follows according to the coordinates of the reference image block and the prediction mode predMode. First, when the coordinates (xRL, yRL) of the reference image block are located outside the reference layer picture rlPic, that is, when the image size of the reference layer picture rlPic is RLPW × RLPH, one of the following conditional expressions is When satisfy | filling, prediction mode predMode [xP] [yP] is set to intra prediction mode (MODE_INTRA).

(xRL <0) || (xRL> = RLPW)
(yRL <0) || (yRL> = RLPH)
Here, the symbol || means a logical sum. When none of the above conditions is satisfied, the prediction mode corresponding to the reference image block is generated by substituting for predMode [xP] [yP] as in the following equation. Here, predModeRL is a prediction mode in the reference layer picture rlPic.

predMode [xP] [yP] = predModeRL [xRL] [yRL];
As a result, when predMode [xP] [yP] is in the inter prediction mode (MODE_INTER), the reference picture index refIdxLX corresponding to each of the reference picture lists L0 and L1, the picture order number refPOCLX corresponding to the reference picture index refIdxLX, and the prediction The prediction parameter of the reference layer picture rlPic corresponding to the list use flag predFlagLX is substituted and set. Specifically, the following formula is applied.

refIdxLX [xP] [yP] = refIdxLXRL [xRL] [yRL];
refPOCLX [xP] [yP] = refPOCLXRL [xRL] [yRL];
predFlagLX [xP] [yP] = predFlagLXRL [xRL] [yRL];
Here, refIdxLXRL is a reference picture index in the reference layer picture rlPic, refPOCLXRL is a picture order number corresponding to the reference picture index refPOCLXRL in the reference layer picture rlPic, and predFlagLXRL is a prediction list use flag in the reference layer picture rlPic is there.

Further, the vector mvLX is derived by the following procedure using the horizontal width SRLPW and vertical width SRLPH of the reference layer corresponding region SRLA, the horizontal width RLPW and vertical width RLPH of the reference layer picture rlPic, and the vector mvLXRL of the reference layer picture rlPic.
(1-A) When the horizontal width SRLPW of the reference layer corresponding area SRLA and the horizontal width RLPW of the reference layer picture are equal, a horizontal component vector mvLX [xP] [yP] [0] is set by the following equation.

mvLX [xP] [yP] [0] = mvLXRL [xRL] [yRL] [0];
(1-B) When the horizontal width SRLPW of the reference layer corresponding region SRLA and the horizontal width RLPW of the reference layer picture are not equal, the horizontal component motion vector of the reference layer picture rlPic is scaled by the following equation, and the horizontal component vector mvLX [xP ] [yP] [0] is set.

scaleFactorMVX = Clip3 (-2 ^ 12, 2 ^ 12-1, ((SRLPW << 8) + (RLPW >> 1)) / RLPW);
mvLX '= Sign (scaleFactorMVX * mvLXRL [xRL] [yRL] [0]) *
((Abs (scaleFactorMVX * mvLXRL [xRL] [yRL] [0]) + 127) >>8);
mvLX [xP] [yP] [0] = Clip3 (-2 ^ 15, 2 ^ 15-1, mvLX ');
(2-A) When the vertical width SRLPH of the reference layer corresponding area SRLA is equal to the vertical width RLPH of the reference layer picture, a vertical component vector mvLX [xP] [yP] [1] is set by the following equation.

mvLX [xP] [yP] [1] = mvLXRL [xRL] [yRL] [1];
(2-B) When the vertical width SRLPH of the reference layer corresponding region SRLA and the horizontal width RLPH of the reference layer picture are not equal, the vertical component motion vector of the reference layer picture rlPic is scaled by the following equation, and the vertical component vector mvLX [ Set xP] [yP] [1].

scaleFactorMVY = Clip3 (-2 ^ 12, 2 ^ 12-1, ((SRLPH << 8) + (RLPH >> 1)) / RLPH);
mvLX '= Sign (scaleFactorMVY * mvLXRL [xRL] [yRL] [1]) *
((Abs (scaleFactorMVY * mvLXRL [xRL] [yRL] [1]) + 127) >>8);
mvLX [xP] [yP] [1] = Clip3 (-2 ^ 15, 2 ^ 15-1, mvLX ');
Here, in the vector mvLX [] [] [], the third array subscripts 0 and 1 represent the horizontal component and the vertical component, respectively.

  On the other hand, when the predMode [xP] [yP] after generation is in the intra prediction mode (MODE_INTRA), the reference picture index refIdxLX corresponding to each of the reference picture lists L0 and L1, and the picture order number refPOCLX corresponding to the reference picture index refIdxLX And the prediction list use flag predFlagLX and the vector mvLX are set to be no reference and zero, respectively. Specifically, it is set by the following formula.

refIdxLX [xP] [yP] = -1;
refPOCLX [xP] [yP] = -1;
predFlagLX [xP] [yP] = 0;
mvLX [xP] [yP] [0] = mvLX [xP] [yP] [1] = 0;
The inter-layer motion mapping unit 313 generates the information of the resample reference layer picture rsPic before starting decoding of the target layer. When the reference layer picture rlPic input from the reference layer picture decoding unit 13 exists and the inter-layer motion prediction flag alt_collocated_indication_flag is 1, the inter-layer motion mapping unit 313 predicts the reference picture based on the following processing. The parameters predMode [xP] [yP], refIdxLX [xP] [yP], mvL0 [xP] [yP], and mvL1 [xP] [yP] are generated.

  The inter-layer motion mapping unit 316 sequentially sets the coordinates (xP, yP) on the resample reference layer picture rsPic so as to be a multiple of 16 from 0 to the width and height of the resample reference layer picture rsPic. . Specifically, the following formula is applied.

xP = xPb <<4;
yP = yPb <<4;
Here, xPb and yPb each set an integer value incremented from 0 to the maximum value as follows.

xPb = 0 ... ((PW + 15) >>4)-1;
yPb = 0 ... ((PH + 15) >>4)-1;
Note that the inter-layer motion mapping unit 316 identifies the reference layer picture rlPic by any of the following methods, and performs inter-layer motion mapping based on the inter-layer correspondence parameter. .

  (Reference layer picture specifying method 1) A reference layer picture specified by collocation information on a slice header is set as a reference layer picture rlPic to be subjected to inter-layer motion mapping. Specifically, the collocation information is included in the slice header, and the list L0 flag collocated_from_L0_flag specified by the list L0 flag collocated_from_L0_flag and the reference index collocated_ref_idx includes an image (reference layer picture) including the reference image block from the reference picture list L0. The reference index collocated_ref_idx indicates the position (index) in the reference picture list of the reference picture. When the layer ID of the reference image colPic specified by collocated_from_L0_flag and collocated_ref_idx is different from the layer ID of the decoding target image, the reference image colPic is set as a reference layer picture that is a target of inter-layer motion mapping.

  (Reference layer picture specifying method 2) When the inter-layer motion prediction flag alt_colloated_indication_flag on the slice header is true (1), the inter-active motion reference layer ActiveMotionPredRefLayerId [collocated_ref_layer_idx] specified by the collocated reference layer ID collocated_ref_layer_idx The reference layer picture rlPic that is the target of

  (Reference layer picture specifying method 3) Among the reference pictures included in the reference picture list, when the layer ID of the reference picture is different from the layer ID of the decoding target image, the reference layer that is the target of inter-layer motion mapping Let it be a picture. Specifically, the layer IDs of the reference pictures in RefPicList0 [] and RefPicList1 [] are scanned, and a reference picture different from the layer ID of the decoding target image is specified.

  As described above, in the inter-layer motion mapping unit 316, the inter-layer correspondence parameters (OffsetL, OffsetT, OffsetR, OffsetB, SRLPW, SRLPH, between the target layer (for example, the enhancement layer) and the reference layer (for example, the base layer), Based on ScaleFactorX, ScaleFactorY, etc.), the reference image block on the reference layer picture rlPic corresponding to the target block on the resample reference layer picture rsPic is determined, and the motion information on the target block is determined based on the motion information on the reference image block Can be generated. Thereby, the effect which improves the precision of the motion information (temporal motion information) used by the motion prediction between layers can be acquired. In particular, for a sequence in which the corresponding region of the target layer and the reference layer changes in units of pictures, compared to the case where inter-layer motion mapping is performed based on the inter-layer correspondence parameter derived from the reference layer corresponding region information, By performing inter-layer motion mapping based on the inter-layer correspondence parameter derived from the active reference layer corresponding region information (reference layer corresponding region information in units of pictures), more motion information (temporal) used in inter-layer motion prediction This has the effect of further improving the accuracy of motion information. Accordingly, the prediction accuracy of inter-layer motion prediction is also improved, so that the encoding efficiency can be improved.

<Modification Example 1 of Prediction Parameter Decoding Unit 302>
In the above example, when the prediction type of the target CU is inter prediction, by specifying a reference image index indicating a reference layer image (resampled reference layer picture rsPic) on the reference image list in each PU unit. It is possible to use inter-layer image prediction. Whether or not to use inter-layer image prediction in the target CU is not limited to the above example, and it is possible to explicitly notify the inter-layer image prediction flag texture_rl_flag within the target CU. FIG. 21 is a diagram illustrating a configuration of encoded data when an inter-layer image prediction flag texture_rl_flag is included in CU units. As shown in FIG. 21, the encoded data in CU units includes an inter-layer image prediction flag (texture_rl_flag) indicated by SYNCU01, CU type information (prediction mode flag (pred_mode_flag)) indicated by SYNCU02, and a PU partition type (part_mode) indicated by SYNCU03. , And PU information and TU information (not shown).

  Hereinafter, the operation of decoding the encoded data when the inter-layer image prediction flag is included in CU units will be described with reference to FIG.

  (S601) The prediction parameter decoding unit 302 uses the variable length decoding unit 301 to decode reference layer designation information and inter-layer prediction type information for each predetermined parameter set (for example, VPS) unit, and the information Based on, an inter-layer image prediction presence / absence flag SamplePredEnableFlag [i] [j] indicating whether or not the target layer i has inter-layer image prediction from the reference layer j is derived. In addition, the variable length decoding unit 301 is used to decode the reference layer corresponding region information for each predetermined parameter set (for example, SPS) unit. Further, the inter-layer image prediction constraint flag is decoded based on the reference layer corresponding region information.

  (S602) The prediction parameter decoding unit 302 uses the variable length decoding unit 301 to decode active reference layer corresponding region information for each predetermined parameter set (for example, slice header) unit. Further, the prediction parameter decoding unit 302, based on the decoded reference layer corresponding region information and active reference layer corresponding region information, position information of the reference layer corresponding region SRLA on each resample reference layer picture rsPic to which the target picture refers Deriving (OffsetL, OffsetT, OffsetR, OffsetB) and size information (SRLPW, SRLPH). Since a specific derivation method has already been described, it will be omitted. Subsequently, the following processing is performed in each CTB.

  (S603) The CU loop is started. The CU loop is performed by sequentially processing all the CUs included in the CTB.

  (S604) The prediction parameter decoding unit 302 derives an inter-layer image prediction applicability flag InterLayerSamplePredEnableFlag and an inter-layer image prediction prohibition flag NoInterlayerSamplePredFlag. The inter-layer image prediction application flag InterLayerSamplePredEnableFlag is derived, for example, by the following equation.

InterlayerSamplePredEnableFlag = SamplePredEnableFlag [curLayerId] [refLayerId]
Here, curLayerId is a layer identifier indicating the target layer i, and refLayerId is a layer identifier indicating the reference layer j. The refLayerId may be notified in advance on the slice header or may be notified in units of CUs.

  Further, the prediction parameter decoding unit 302 is based on the inter-layer image prediction constraint flag, the coordinates (xP, yP) of the upper left pixel of the target CU, and the CU size log2CbSize (represented by a logarithmic value with the CU size being 2 as a base) The inter-layer image prediction prohibition flag NoInterLayerSamplePredFlag is derived. Specifically, when the inter-layer image prediction restriction flag is 0, the inter-layer image prediction prohibition flag is set to 0 (NoInterLayerSamplePredFlag = 0). On the other hand, when the inter-layer image prediction constraint flag is 1, the corresponding region on the resample reference layer picture rsPic corresponding to the target CU on the target picture curPic is (an inter-layer referring to an image outside the reference layer corresponding region). If any of the conditions (A1) to (A4) described in “Image prediction” is satisfied, the inter-layer image prediction prohibition flag is set to 1 (NoInterLayerSamplePredFlag = 1). Otherwise, the inter-layer image is set. Set the prediction prohibition flag to 0 (NoInterLayerSamplePredFlag = 0). Note that the vertical width of the target CU is hPb (= log2CbSize << 1) and the horizontal width wPb (= log2CbSize).

  (S605) It is determined whether the target layer curLayerId, the inter-layer image prediction applicable flag InterLayerSamplePredEnableFlag, and the inter-layer image prediction prohibition flag NoInterLayerSamplePredFlag satisfy the following expression (J-1).

curLayerId> 0 &&
InterLayerSamplePredEnableFlag &&! NoInterLayerSamplePredFlag? 1: 0; (J-1)
That is, it is determined whether or not the layer identifier curLayerId of the target layer is greater than 0 (is an enhancement layer), the inter-layer image prediction applicability flag is true, and the inter-layer image prediction prohibition flag is false. In Formula (J-1), when the value is true (Yes in S605), the process proceeds to step S606, and the inter-layer image prediction flag texture_rl_flag (SYNCU01 in FIG. 21) is decoded (S606). In other cases (when the value of the expression (J-1) is false), the process proceeds to step S607, decoding of the inter-layer image prediction flag texture_rl_flag is omitted, and the value of texture_rl_flag is set to zero (S607).

  (S608) It is determined whether the value of the inter-layer image prediction flag is 1. When the value of the flag is true, the process proceeds to step S611. If the value of the flag is false, the process proceeds to step S609.

  (S609) The CU type information indicating the CU type of the target CU, for example, the prediction mode flag (pred_mode_flag) shown in SYNCU02 on FIG. 21 is decoded. Based on the prediction mode flag, it is determined whether the CU type of the target CU, that is, an intra CU or an inter CU. When the prediction mode flag is 1, it indicates an intra CU, and when it is 0, it indicates an inter CU. In the case of an inter CU, PU partition type information (part_mode) shown in SYNCU03 on FIG. 21 can be further decoded after the prediction mode flag.

  (S610) PU information of each PU unit included in the target CU is decoded.

  (S611) The TU information of each TU unit included in the target CU is decoded.

  (S612) This is the end of the loop in CU units.

  According to the modification 1 of the prediction parameter decoding unit 302, whether or not to explicitly decode the inter-layer image prediction flag (texture_rl_flag) of the target CU (target prediction unit) is determined between the inter-layer image prediction applicable flag and the inter-layer. Control is performed based on the image prediction prohibition flag. In particular, when the inter-layer image prediction constraint flag indicating that inter-layer image prediction including pixels outside the reference layer corresponding region SRLA specified by the reference layer corresponding region information or the active reference layer corresponding region information is 1 is 1. It is ensured between the image decoding device and the image coding device that inter-layer image prediction in which the corresponding region on the resample reference layer picture rsPic corresponding to the target CU straddles the reference layer corresponding region SRLA is not used. Therefore. When the corresponding region on the resample reference layer picture rsPic corresponding to the target CU straddles the reference layer corresponding region SRLA (when any of the above conditions (A1) to (A4) is satisfied), decoding of the inter-layer image prediction flag By omitting (ie, estimating that the inter-layer image prediction flag is 0), it is possible to reduce the processing amount related to decoding of the inter-layer image prediction flag. Moreover, since the amount of codes related to the inter-layer image prediction flag can be reduced, the effect of improving the code efficiency is achieved. In addition, since it is compensated that pixels outside the reference layer corresponding region SRLA on the resample reference layer picture rsPic are not referenced in the inter-layer image prediction, the pixels outside the reference layer corresponding region are inter-layer image mapped (resampling). Processing generated by (processing) can be omitted. Further, in the reference picture memory, it is possible to reduce a memory for holding pixels outside the reference layer corresponding area SRLA on the resample reference layer picture rsPic.

<Modification Example 2 of Prediction Parameter Decoding Unit 302>
In the above example, when the inter-layer image prediction constraint flag is 1, an inter-layer image that refers to a pixel outside the reference layer corresponding region SRLA specified by the reference layer corresponding region information or the active reference layer corresponding region information. The description is based on the assumption that the use of prediction is prohibited, but the present invention is not limited to this. When the inter-layer image prediction constraint flag is 1, use of inter-layer image prediction that refers only to pixels outside the reference layer corresponding region SRLA specified by the reference layer corresponding region information or the active reference layer corresponding region information is prohibited. You may show that.

  In this case, in step S604, the conditional expression for deriving the inter-layer image prediction prohibition flag is set to (an inter-layer image that refers only to an image outside the reference layer corresponding region, instead of the above-described conditions (A1) to (A4)). The conditions (B1) to (B4) described in (about prediction) are replaced.

  According to the second modification of the prediction parameter decoding unit 302, whether or not to explicitly decode the inter-layer image prediction flag (texture_rl_flag) of the target CU is determined based on whether an inter-layer image prediction application flag and an inter-layer image prediction prohibition flag. Control based on. In particular, when the inter-layer image prediction constraint flag is 1, inter-layer image prediction in which the corresponding region on the resample reference layer picture rsPic corresponding to the target CU refers only to pixels outside the reference layer corresponding region SRLA is not used. Is guaranteed between the image decoding apparatus and the image encoding apparatus. Therefore. When the corresponding region on the resample reference layer picture rsPic corresponding to the target CU refers only to a pixel outside the reference layer corresponding region SRLA (when any of the above conditions (B1) to (B4) is satisfied), between layers By omitting decoding of the image prediction flag (that is, estimating that the inter-layer image prediction flag is 0), it is possible to reduce the processing amount related to decoding of the inter-layer image prediction flag. Moreover, since the amount of codes related to the inter-layer image prediction flag can be reduced, the effect of improving the code efficiency is achieved.

(Hierarchical video decoding device with bitstream restriction)
Note that, according to the hierarchical video decoding device described above, the inter-layer image prediction constraint flag is decoded, and when the flag is true, the prediction image of the prediction unit is generated by inter-layer image prediction that does not satisfy the predetermined condition. However, the bit stream restriction may be used instead of the inter-layer image prediction restriction flag.

  That is, in a specific profile (for example, a scalable extension profile), the hierarchical video decoding apparatus according to the present embodiment requests the following conditions (CF conditions) as bitstream conformance.

When the prediction method of the prediction unit is inter-layer image prediction, inter-layer image prediction that satisfies a predetermined condition must not be performed ... CF condition The CF condition is the same as the following condition.

When the prediction method of the prediction unit is inter-layer image prediction, inter-layer image prediction that does not satisfy a predetermined condition is performed ... CF condition Note that bitstream conformance is a hierarchical video decoding device (here, the present invention) This is a condition that the bitstream to be decoded by the hierarchical video decoding device according to the embodiment needs to satisfy.

  In this case, the hierarchical image decoding device may generate a prediction image of the prediction unit by inter-layer image prediction that does not satisfy the predetermined condition when the prediction method of the prediction unit is inter-layer image prediction. Features.

[Hierarchical video encoding device]
Below, the structure of the hierarchy moving image encoder 2 which concerns on this embodiment is demonstrated with reference to FIG.

(Configuration of Hierarchical Video Encoding Device)
A schematic configuration of the hierarchical moving image encoding device 2 will be described with reference to FIG. FIG. 23 is a functional block diagram showing a schematic configuration of the hierarchical video encoding device 2. The hierarchical video encoding device 2 encodes the input image PIN # T of the target layer with reference to the reference layer encoded data DATA # R to generate hierarchical encoded data DATA of the target layer. It is assumed that the reference layer encoded data DATA # R has been encoded in the hierarchical video encoding apparatus corresponding to the reference layer.

  As shown in FIG. 23, the hierarchical video encoding device 2 includes a target layer picture encoding unit 22, a NAL multiplexing unit 21, and a reference layer picture decoding unit 13.

  The target layer picture encoding unit 22 encodes the input image PIN # T and outputs it as target layer encoded data DATA # T. Also, the target layer picture encoding unit 22 uses inter-layer image prediction using the reference layer decoded picture decoded by the reference layer picture decoding unit 13 in order to encode the input image PIN # T.

  The NAL multiplexing unit 213 generates NAL-multiplexed hierarchical video encoded data DATA by storing input target layer encoded data DATA # T and reference layer encoded data DATA # R in the NAL unit. And output to the outside.

  The reference layer picture decoding unit 13 is the same component as the reference layer decoding unit 13 included in the hierarchical video decoding device 1 that has already been described, and detailed description thereof is omitted.

(Target Layer Picture Encoding Unit 22 (Image Encoding Device))
The detailed configuration of the target layer picture encoding unit 22 will be described with reference to FIG. FIG. 24 is a functional block diagram illustrating the configuration of the target layer picture encoding unit 22. The image target layer picture encoding unit 22 includes a prediction image generation unit 101, a subtraction unit 102, a DCT / quantization unit 103, a variable length encoding unit 104, an inverse quantization / inverse DCT unit 105, an addition unit 106, and a prediction parameter memory. (Prediction parameter storage unit, frame memory) 108, reference picture memory (reference image storage unit, frame memory) 109, encoding parameter determination unit 110, prediction parameter encoding unit 111, reference layer corresponding region estimation unit 114, and resampling unit 314 is configured. The prediction parameter encoding unit 111 includes an inter prediction parameter encoding unit 112 and an intra prediction parameter encoding unit 113. The resampling unit 314 includes an inter-layer image mapping unit 315 and an inter-layer motion mapping unit 316. Note that the resampling unit 314 has the same configuration as the resampling unit 314 in the image decoding apparatus.

  The resampling unit 314 includes an inter-layer image prediction constraint flag recorded in the prediction parameter memory 108, reference layer corresponding region information and active reference layer corresponding region information recorded in the prediction parameter memory 108, and a reference layer picture decoding unit. Using the motion information rlPicMotion and the image rlPicSample of the reference layer decoded picture (referred to as reference layer picture rlPic) decoded by 15, the resample motion information rsPicMotion and the resampled image rsPicSample of the resample reference layer picture rsPic are respectively inter-layer motion. The mapping unit 316 and the inter-layer image mapping unit 315 generate them. The generated resample motion information rsPicMotion is stored in the prediction parameter memory 108. The generated resample image rsPicSample is stored in the reference picture memory 109. Note that the inter-layer image mapping unit 315 and the inter-layer motion mapping unit 316 are the same as the target layer picture decoding unit 12, and thus the description thereof is omitted. However, the prediction parameter memory 307 and the reference picture memory 308 are replaced with the prediction parameter memory 108 and the reference picture memory 109 for interpretation.

  The predicted image generation unit 101 generates a predicted picture block P for each block which is an area obtained by dividing the picture of the input image PIN # T of the target layer input from the outside. Here, the predicted image generation unit 101 reads the reference picture block from the reference picture memory 109 based on the prediction parameter input from the prediction parameter encoding unit 111. The prediction parameter input from the prediction parameter encoding unit 111 is, for example, a motion vector or a displacement vector. The predicted image generation unit 101 reads the reference picture block of the block at the position indicated by the motion vector or the displacement vector predicted from the encoding target block. The prediction image generation unit 101 generates a prediction picture block P using one prediction method among a plurality of prediction methods for the read reference picture block. The predicted image generation unit 101 outputs the generated predicted picture block P to the subtraction unit 102. Note that since the predicted image generation unit 101 performs the same operation as the predicted image generation unit 308 already described, details of generation of the predicted picture block P are omitted.

  The subtraction unit 102 subtracts the signal value of the prediction picture block P input from the prediction image generation unit 101 for each pixel from the signal value of the corresponding block of the input image PIN # T of the target layer input from the outside. Generate a residual signal. The subtraction unit 102 outputs the generated residual signal to the DCT / quantization unit 103.

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

  The variable length coding unit 104 receives the quantization coefficient from the DCT / quantization unit 103 and the coding parameter from the prediction parameter coding unit 111. Input coding parameters include, for example, prediction mode predMode, partition mode part_mode, merge flag merge_flag, merge index merge_idx, inter prediction flag inter_pred_idc, reference picture index refIdxLX, prediction vector index mvp_LX_idx, difference vector mvdLX, number of layers vps_max_layers_minus1 ( SYNVPS01 in FIG. 3), layer identifier designation information (SYNVPS02 in FIG. 3), reference layer designation information (SYNVPS04 in FIG. 3), layer dependent type information (SYNVPS05 in FIG. 3), reference layer corresponding area information (FIG. 5), inter-layer image prediction constraint flag (SYNSPS03 in FIG. 5), active reference layer designation information (SYNSH01 in FIG. 7), active reference layer corresponding region information (SYNSH02 in FIG. 7), collocated information collocated_from_l0_flag , Collocated_ref_idx, alt_collocated_indication_flag, and collocated_ref_layer_idex.

  The variable length coding unit 104 performs variable length coding on the input quantization coefficient and coding parameter, generates target layer coded data DATA # T, and outputs it to the outside.

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

  The addition unit 106 adds the signal value of the predicted picture block P input from the predicted image generation unit 101 and the signal value of the decoded residual signal input from the inverse quantization / inverse DCT unit 105 for each pixel, and refers to them. Generate a picture block. The adding unit 106 stores the generated reference picture block in the reference picture memory 109.

  The prediction parameter memory 108 stores the prediction parameter generated by the prediction parameter encoding unit 111 at a predetermined position for each picture and block to be encoded.

  The reference picture memory 109 stores the reference picture block generated by the addition unit 106 at a predetermined position for each picture and block to be encoded.

  The encoding parameter determination unit 110 selects one set from among a plurality of sets of encoding parameters. The encoding parameter is a parameter to be encoded that is generated in association with the above-described prediction parameter or the prediction parameter.

  The encoding parameter determination unit 110 calculates a cost value indicating the amount of information and the encoding error for each of the plurality of sets of the encoding parameters. The cost value is, for example, the sum of a code amount and a square error multiplied by a coefficient λ. The code amount is the information amount of the target layer encoded data DATA # T obtained by variable-length encoding the quantization error and the encoding parameter. The square error is the sum between pixels regarding the square value of the residual value of the residual signal calculated by the subtracting unit 102. The coefficient λ is a real number larger than a preset zero. The encoding parameter determination unit 110 selects a set of encoding parameters that minimizes the calculated cost value. Thereby, the variable length coding unit 104 outputs the selected set of coding parameters to the outside as the target layer coded data DATA # T, and does not output the set of coding parameters not selected.

  The set of coding parameters that are selected depends on the prediction scheme that is selected. The prediction method to be selected is intra prediction, motion prediction, and merge prediction when the encoding target picture is a base layer picture. Motion prediction is prediction between display times among the above-mentioned inter predictions. The merge prediction is a prediction that uses the same reference picture block and prediction parameter as a block that has already been encoded and is within a predetermined range from the encoding target block. When the picture to be encoded is a picture of an upper layer (enhancement layer), the prediction methods to be selected are intra prediction, motion prediction, merge prediction, and inter-layer prediction (inter-layer image prediction, inter-layer prediction). Motion prediction).

  The encoding parameter determination unit 110 outputs the prediction mode predMode corresponding to the selected prediction method to the prediction parameter encoding unit 111. For example, when motion prediction is selected as the prediction method, the encoding parameter determination unit 110 also outputs a motion vector mvLX. The motion vector mvLX indicates a vector from the position of the encoding target block to the position of the reference picture block when the predicted picture block P is generated. The information indicating the motion vector mvLX may include information indicating a reference picture (for example, a reference picture index refIdxLX, a picture order number POC), and may represent a prediction parameter. When inter-layer prediction is selected as the prediction method, the encoding parameter determination unit 110 also outputs a displacement vector mvLX. The displacement vector mvLX indicates a vector from the position of the encoding target block to the position of the reference picture block when the predicted picture block P is generated. The information indicating the displacement vector mvLX may include information indicating a reference picture (for example, a reference picture index refIdxLX, a layer identifier layer_id) and may represent a prediction parameter. When merge prediction is selected as the prediction method, the encoding parameter determination unit 110 also outputs a merge index merge_idx.

  Note that the encoding parameter determination unit 110 has a corresponding region on the rsPic on the resample reference picture that the inter-layer image prediction constraint flag is true (1) and can be referred to by the target prediction unit (from the reference layer corresponding region). When any one of the conditions (A1) to (A4) described in “Inter-layer image prediction referring to the outer image” is satisfied, the inter-layer image prediction (referring to different layers) is performed as the prediction method of the target prediction unit. It is assumed that intra prediction or inter prediction on the same layer is selected without selecting (inter prediction). That is, a prediction parameter including a reference picture index that satisfies the above condition is not included in the encoded data. Instead of the conditions (A1) to (A4), the conditions (B1) to (B4) described in (Inter-layer image prediction that refers only to images outside the reference layer corresponding region) may be used. In inter prediction, it is possible to use inter-layer image prediction by specifying a reference image index indicating a reference layer image (resampled reference layer picture rsPic) on the reference image list.

  The prediction parameter encoding unit 111 derives a prediction parameter to be used when generating a prediction picture based on the parameter input from the encoding parameter determination unit 110, encodes the derived prediction parameter, and sets a set of encoding parameters. Generate. The prediction parameter encoding unit 111 outputs the generated set of encoding parameters to the variable length encoding unit 104.

  The prediction parameter encoding unit 111 stores, in the prediction parameter memory 108, a prediction parameter corresponding to the one selected by the encoding parameter determination unit 110 from the generated set of encoding parameters.

  The prediction parameter encoding unit 111 operates the inter prediction parameter encoding unit 112 when the prediction mode predMode input from the encoding parameter determination unit 110 indicates the inter prediction mode. The prediction parameter encoding unit 111 operates the intra prediction parameter encoding unit 113 when the prediction mode predMode indicates the intra prediction mode.

  The inter prediction parameter encoding unit 112 derives an inter prediction parameter based on the prediction parameter input from the encoding parameter determination unit 110. The inter prediction parameter encoding unit 112 includes the same configuration as the configuration in which the inter prediction parameter decoding unit 303 derives the inter prediction parameter (see FIGS. 15 and 17) as a configuration for deriving the inter prediction parameter. The configuration of the inter prediction parameter encoding unit 112 will be described later.

  The intra prediction parameter encoding unit 113 determines the intra prediction mode IntraPredMode indicated by the prediction mode predMode input from the encoding parameter determination unit 110 as a set of intra prediction parameters.

  The reference layer corresponding region estimation unit 114, from the input target layer image and the reference layer picture rlPic image rlSample input from the reference layer picture decoding unit 13, the reference layer corresponding to the target layer and the reference layer corresponding region Region information (reference layer corresponding region information common to the entire sequence (SYNSPS02 in FIG. 5), reference layer corresponding region information in units of pictures (SYNSH02 in FIG. 7 or SYNSH03 in FIG. 8)) is calculated, and a prediction parameter encoding unit To 111. For example, the reference layer corresponding region estimation unit 114 first extracts feature points such as edges and corner points between pictures of the target layer and the reference layer at the same time, and calculates feature points based matching between the feature points. To calculate a parameter (for example, a projective transformation matrix or a rotation matrix and a translation vector) indicating the association between images. Basically, in scalable coding, the target layer and the reference layer are images having different spatial magnifications and positions, and therefore, what needs to be calculated is the magnification (x direction, y direction) and translation. It is a vector (x direction, y direction). A parameter indicating the positional relationship between the picture of the target layer and the reference layer corresponding region (reference layer corresponding region information (offsetL, offsetT, offsetR, offsetB, etc.)) is derived from the calculated parameter indicating the correlation between images, and the prediction parameter It outputs to the encoding part 111. In addition, the reference layer corresponding | compatible area estimation part 114 is not included, but the correspondence (reference layer corresponding | compatible area information) of an object layer and a reference layer is known, and you may input from the outside. .

  The prediction parameter encoding unit 111 converts each syntax from the reference layer corresponding region information input from the reference layer corresponding region estimation unit 114 to, for example, equations (I-1) to (I-4), (I-1B) to Derived by (I-4B) or the like, and encodes each derived syntax. The reference layer corresponding area information is output in units of slice layers, picture layers, or sequence layers. Moreover, the prediction parameter encoding unit 111 further includes an inter-layer information deriving unit 1160 (not shown). The inter-layer information deriving unit 1160 has the same function as the inter-layer information deriving unit 3020 included in the prediction parameter decoding unit 302. Based on the encoded reference layer corresponding region information, offset OffsetL indicating the position of the reference layer corresponding region SRLA on the resampled reference layer picture rsPic as an inter-layer correspondence parameter regarding the reference layer j referred to by the target layer i, OffsetT, OffsetR, and OffsetB are derived using the above equations (G-1) to (G-4), and the horizontal width SRLPW and the vertical width SRLPH of the reference layer corresponding region SRLA are derived from the above equations (G-5) to (G -6).

  Subsequently, if there is active reference layer corresponding area information corresponding to the reference layer j referred to by the target layer i, the offsets OffsetL, OffsetT, OffsetR, OffsetB indicating the position of the reference layer corresponding area SRLA using the information, and the reference The horizontal width SRLPW and vertical width SRLPH of the layer corresponding area SRLA are reset.

  Subsequently, the horizontal width size ratio ScaleFactorX and the vertical width size ratio ScaleFactorY of the reference layer corresponding region SRLA and the reference layer picture rlPic are derived using the above-described equations (G-7) to (G-8).

  Inter-layer correspondence parameters (OffsetL, OffsetT, OffsetR, OffsetB, SRLPW, SRLPH, ScaleFactorX, ScaleFactorY, etc.) derived by the inter-layer information deriving unit 1160 are stored in the prediction parameter memory 108.

  Furthermore, the prediction parameter encoding unit 111 encodes the inter-layer image prediction constraint flag based on the reference layer corresponding region information. If there is the reference layer corresponding region information, the inter-layer prediction image constraint flag is encoded. If there is no reference layer corresponding region information, the value of the inter-layer image constraint flag is estimated as 0, and the encoding is omitted. Note that the value of the inter-layer image prediction constraint flag may be determined by the encoding parameter determination unit 110 or may be designated from the outside.

(Inter prediction parameter encoding unit 112)
The configuration of the inter prediction parameter encoding unit 112 will be described. The inter prediction parameter encoding unit 112 is means corresponding to the inter prediction parameter decoding unit 303 in the image decoding apparatus.

  FIG. 25 is a schematic diagram illustrating a configuration of the inter prediction parameter encoding unit 112 according to the present embodiment. The inter prediction parameter encoding unit 112 includes a merge prediction parameter deriving unit 1121, an AMVP prediction parameter deriving unit 1122, a subtracting unit 1123, and an inter prediction parameter encoding control unit 1124.

  The merge prediction parameter derivation unit 1121 has the same configuration as the merge prediction parameter derivation unit 3036 (see FIG. 15).

  The merge index merge_idx is input from the encoding parameter determination unit 110 to the merge prediction parameter derivation unit 1121 when the prediction mode predMode input from the encoding parameter determination unit 110 indicates the merge prediction mode. The merge index merge_idx is output to the inter prediction parameter encoding control unit 1124. The merge prediction parameter derivation unit 1121 reads the reference picture index refIdxLX and the vector mvLX of the reference block indicated by the merge index merge_idx from the prediction candidates from the prediction parameter memory 108. The merge candidate is a reference block (for example, a reference block in contact with the lower left end, upper left end, and upper right end of the encoding target block) within a predetermined range from the encoding target block to be encoded, This is a reference block for which the encoding process has been completed.

  The AMVP prediction parameter derivation unit 1122 has the same configuration as the AMVP prediction parameter derivation unit 3032 (see FIG. 17).

  When the prediction mode predMode input from the encoding parameter determination unit 110 indicates the inter prediction mode, the vector mvLX is input from the encoding parameter determination unit 110 to the AMVP prediction parameter derivation unit 1122. The AMVP prediction parameter derivation unit 1122 derives a prediction vector mvpLX based on the input vector mvLX. The AMVP prediction parameter derivation unit 1122 outputs the derived prediction vector mvpLX to the subtraction unit 1123. Note that the reference picture index refIdx and the vector index mvp_LX_idx are output to the inter prediction parameter encoding control unit 1124.

  The subtraction unit 1123 subtracts the prediction vector mvpLX input from the AMVP prediction parameter derivation unit 1122 from the vector mvLX input from the encoding parameter determination unit 110 to generate a difference vector mvdLX. The difference vector mvdLX is output to the inter prediction parameter encoding control unit 1124.

  The inter prediction parameter coding control unit 1124 instructs the variable length coding unit 104 to code a code (syntax element) related to inter prediction, and divides the code (syntax element) included in the encoded data, for example The mode part_mode, merge flag merge_flag, merge index merge_idx, inter-prediction identifier inter_pred_idc, reference picture index refIdxLX, prediction vector index mvp_LX_idx, and difference vector mvdLX are encoded.

  The inter prediction parameter encoding control unit 1124 outputs the merge index merge_idx input from the encoding parameter determination unit 110 to the variable length encoding unit 104 when the prediction mode predMode indicates the merge prediction mode.

  When the prediction mode predMode indicates the inter prediction mode, the inter prediction parameter encoding control unit 1124 receives the reference picture index refIdxLX and the vector index mvp_LX_idx input from the encoding parameter determination unit 110, and the difference input from the subtraction unit 1123. Vector mvdLX is output to variable length coding section 104.

  As described above, in the inter-layer image mapping unit 315, the inter-layer correspondence parameters (OffsetL, OffsetT, OffsetR, OffsetB, SRLPW, SRLPH, and the like between the target layer (for example, the enhancement layer) and the reference layer (for example, the base layer) Based on ScaleFactorX, ScaleFactorY, etc.), the position of the reference pixel on the reference layer picture rlPic corresponding to each pixel on the resample reference layer picture rsPic is determined, and a predetermined resample filter is applied to the reference pixel and surrounding pixels Thus, the target pixel can be generated. Thereby, the effect which improves the precision of the resample image used by the image prediction between layers can be acquired. In particular, for a sequence in which the corresponding region of the target layer and the reference layer changes in units of pictures, compared to the case of performing inter-layer image mapping based on the inter-layer correspondence parameter derived from the reference layer corresponding region information, By performing the inter-layer image mapping based on the inter-layer correspondence parameter derived from the active reference layer corresponding region information, there is an effect of further improving the accuracy of the resampled image used in the inter-layer image prediction. As a result, the prediction accuracy of inter-layer image prediction is also improved, so that the encoding efficiency can be improved.

  As described above, in the inter-layer motion mapping unit 316, the inter-layer correspondence parameters (OffsetL, OffsetT, OffsetR, OffsetB, SRLPW, SRLPH, between the target layer (for example, the enhancement layer) and the reference layer (for example, the base layer), Based on ScaleFactorX, ScaleFactorY, etc.), the reference image block on the reference layer picture rlPic corresponding to the target block on the resample reference layer picture rsPic is determined, and the motion information on the target block is determined based on the motion information on the reference image block Can be generated. Thereby, the effect which improves the precision of the motion information (temporal motion information) used by the motion prediction between layers can be acquired. In particular, for a sequence in which the corresponding region of the target layer and the reference layer changes in units of pictures, compared to the case where inter-layer motion mapping is performed based on the inter-layer correspondence parameter derived from the reference layer corresponding region information, Effect of further improving the accuracy of motion information (temporal motion information) used in inter-layer motion prediction by performing inter-layer motion mapping based on inter-layer correspondence parameters derived from active reference layer corresponding region information Play. Accordingly, the prediction accuracy of inter-layer motion prediction is also improved, so that the encoding efficiency can be improved.

<Modification Example 1 of Prediction Parameter Encoding Unit 111>
In the above example, when the prediction type of the target CU is inter prediction, by specifying a reference image index indicating a reference layer image (resampled reference layer picture rsPic) on the reference image list in each PU unit. It is possible to use inter-layer image prediction. Whether or not to use inter-layer image prediction in the target CU is not limited to the above example, and it is possible to explicitly notify the inter-layer image prediction flag texture_rl_flag within the target CU. FIG. 21 is a diagram illustrating a configuration of encoded data when an inter-layer image prediction flag texture_rl_flag is included in CU units. As shown in FIG. 21, the encoded data in CU units includes an inter-layer image prediction flag (texture_rl_flag) indicated by SYNCU01, CU type information (prediction mode flag (pred_mode_flag)) indicated by SYNCU02, and a PU partition type (part_mode) indicated by SYNCU03. , And PU information and TU information (not shown).

  Hereinafter, the operation of encoding the encoded data when the inter-layer image prediction flag is included in CU units will be described with reference to FIG. Note that the first modification of the prediction parameter encoding unit 111 corresponds to the inverse process of the prediction parameter decoding unit 302.

(S701) The prediction parameter encoding unit 111 is based on the reference layer designation information and the inter-layer prediction type information determined by the encoding parameter determination unit 110 for each predetermined parameter set (for example, VPS) unit. The target layer i derives an inter-layer image prediction presence / absence flag SamplePredEnableFlag [i] [j] indicating whether inter-layer image prediction is performed from the reference layer j.
Also, the prediction parameter encoding unit 111 instructs the variable length encoding unit 104 to encode the reference layer designation information and the code of the inter-layer prediction type information. Further, the prediction parameter encoding unit 111 instructs the variable length encoding unit 104 to code the reference layer corresponding region information determined by the encoding parameter determining unit 110 for each predetermined parameter set (for example, SPS) unit. To encode. Furthermore, the prediction parameter encoding unit 111 instructs the variable length encoding unit 104 to encode the inter-layer image prediction constraint flag determined based on the reference layer corresponding region information in the encoding parameter determination unit 110. .

  (S702) The prediction parameter encoding unit 111 transmits the code of the active reference layer corresponding region information determined by the encoding parameter determination unit 110 to the variable length encoding unit 104 for each predetermined parameter set (for example, slice header) unit. Direct and encode. Further, the prediction parameter encoding unit 111, based on the reference layer corresponding region information determined by the encoding parameter determining unit 110 and the active reference layer corresponding region information, on each resample reference layer picture rsPic that the target picture refers to Position information (OffsetL, OffsetT, OffsetR, OffsetB) and size information (SRLPW, SRLPH) of the reference layer corresponding region SRLA are derived. Since a specific derivation method has already been described, it will be omitted. Subsequently, the following processing is performed in each CTB.

  (S703) A CU loop is started. The CU loop is performed by sequentially processing all the CUs included in the CTB.

  (S704) The prediction parameter encoding unit 111 derives an inter-layer image prediction applicability flag InterLayerSamplePredEnableFlag and an inter-layer image prediction prohibition flag NoInterlayerSamplePredFlag. Note that the method of deriving the inter-layer image prediction application flag and the inter-layer image prediction prohibition flag is the same as S604 in FIG.

  (S705) The prediction parameter encoding unit 111 determines whether the target layer curLayerId, the inter-layer image prediction applicability flag InterLayerSamplePredEnableFlag, and the inter-layer image prediction prohibition flag NoInterLayerSamplePredFlag satisfy the above formula (J-1). In Formula (J-1), when the value is true (Yes in S705), the process proceeds to step S706, and the prediction parameter encoding unit 111 determines the inter-layer image prediction flag texture_rl_flag (determined by the encoding parameter determination unit 110). 21 is instructed to the variable length encoding unit 110 to encode (S706). In other cases (when the value of Expression (J-1) is false), encoding of the inter-layer image prediction flag texture_rl_flag is omitted, and the process proceeds to step S708.

  (S708) It is determined whether the value of the inter-layer image prediction flag is 1. When the value of the flag is true, the process proceeds to step S711. If the value of the flag is false, the process proceeds to step S709.

  (S709) The CU type information indicating the CU type of the target CU, for example, the prediction mode flag (pred_mode_flag) shown in SYNCU02 on FIG. 21 is encoded. When the prediction mode flag is 0, PU partition type information (part_mode) shown in SYNCU03 on FIG. 21 can be further encoded after encoding the prediction mode flag.

  (S710) PU information of each PU unit included in the target CU is encoded.

  (S711) TU information of each TU unit included in the target CU is encoded.

  (S712) This is the end of the loop in CU units.

  According to the first modification of the prediction parameter encoding unit 111, whether or not to explicitly encode the inter-layer image prediction flag (texture_rl_flag) of the target CU is determined based on whether the inter-layer image prediction application flag and the inter-layer image prediction are prohibited. Control based on the flag. In particular, when the inter-layer image prediction constraint flag indicating that inter-layer image prediction including pixels outside the reference layer corresponding region SRLA specified by the reference layer corresponding region information or the active reference layer corresponding region information is 1 is 1. It is ensured between the image decoding device and the image coding device that inter-layer image prediction in which the corresponding region on the resample reference layer picture rsPic corresponding to the target CU straddles the reference layer corresponding region SRLA is not used. Therefore. When the corresponding region on the resample reference layer picture rsPic corresponding to the target CU straddles the reference layer corresponding region SRLA (when any of the above conditions (A1) to (A4) is satisfied), the code of the inter-layer image prediction flag By omitting the encoding, it is possible to reduce the processing amount related to the encoding of the inter-layer image prediction flag. Moreover, since the amount of codes related to the inter-layer image prediction flag can be reduced, the effect of improving the code efficiency is achieved. In addition, since it is compensated that pixels outside the reference layer corresponding region SRLA on the resample reference layer picture rsPic are not referenced in the inter-layer image prediction, the pixels outside the reference layer corresponding region are inter-layer image mapped (resampling). Processing generated by (processing) can be omitted. Further, in the reference picture memory, it is possible to reduce a memory for holding pixels outside the reference layer corresponding area SRLA on the resample reference layer picture rsPic.

<Modification Example 2 of Prediction Parameter Encoding Unit 111>
In the above example, when the inter-layer image prediction constraint flag is 1, an inter-layer image that refers to a pixel outside the reference layer corresponding region SRLA specified by the reference layer corresponding region information or the active reference layer corresponding region information. The description is based on the assumption that the use of prediction is prohibited, but the present invention is not limited to this. When the inter-layer image prediction constraint flag is 1, use of inter-layer image prediction that refers only to pixels outside the reference layer corresponding region SRLA specified by the reference layer corresponding region information or the active reference layer corresponding region information is prohibited. You may show that.

  In this case, in step S704, the conditional expression for deriving the inter-layer image prediction prohibition flag may be replaced with the above conditions (B1) to (B4) instead of the above conditions (A1) to (A4).

  According to the second modification of the prediction parameter encoding unit 111, whether or not to explicitly encode the inter-layer image prediction flag (texture_rl_flag) of the target CU is determined based on whether the inter-layer image prediction application flag and the inter-layer image prediction are used. Control based on the prohibition flag. In particular, when the inter-layer image prediction constraint flag is 1, inter-layer image prediction in which the corresponding region on the resample reference layer picture rsPic corresponding to the target CU refers only to pixels outside the reference layer corresponding region SRLA is not used. Is guaranteed between the image decoding apparatus and the image encoding apparatus. Therefore. When the corresponding region on the resample reference layer picture rsPic corresponding to the target CU refers only to a pixel outside the reference layer corresponding region SRLA (when any of the above conditions (B1) to (B4) is satisfied), between layers By omitting the encoding of the image prediction flag, the processing amount related to the encoding of the inter-layer image prediction flag can be reduced. Moreover, since the amount of codes related to the inter-layer image prediction flag can be reduced, the effect of improving the code efficiency is achieved.

(Application example to other hierarchical video encoding / decoding systems)
The above-described hierarchical video encoding device 2 and hierarchical video 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.

  Based on FIG. 27, it will be described that the above-described hierarchical video encoding device 2 and hierarchical video decoding device 1 can be used for transmission and reception of video. FIG. 27A is a block diagram illustrating a configuration of a transmission device PROD_A in which the hierarchical video encoding device 2 is mounted.

  As illustrated in FIG. 27A, the transmission apparatus PROD_A modulates a carrier wave with an encoding unit PROD_A1 that obtains encoded data by encoding a moving image, and with the encoded data obtained by the encoding unit PROD_A1. Thus, a modulation unit PROD_A2 that obtains a modulation signal and a transmission unit PROD_A3 that transmits the modulation signal obtained by the modulation unit PROD_A2 are provided. The hierarchical 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, an input terminal PROD_A6 that inputs the moving image from the outside, as a supply source of the moving image input to the encoding unit PROD_A1. An image processing unit A7 that generates or processes an image may be further provided. FIG. 27A illustrates a configuration in which the transmission apparatus PROD_A includes all of these, but a part 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. 27B is a block diagram illustrating a configuration of a receiving device PROD_B in which the hierarchical video decoding device 1 is mounted. As illustrated in FIG. 27B, the receiving device PROD_B includes a receiving unit PROD_B1 that receives a modulated signal, a demodulating unit PROD_B2 that obtains encoded data by demodulating the modulated signal received by the receiving unit PROD_B1, and a demodulator A decoding unit PROD_B3 that obtains a moving image by decoding the encoded data obtained by the unit PROD_B2. The above-described hierarchical video decoding device 1 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. 27B illustrates a configuration in which the reception apparatus PROD_B includes all of these, but a part of the configuration 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.

  Based on FIG. 28, it will be described that the above-described hierarchical video encoding device 2 and hierarchical video decoding device 1 can be used for recording and reproduction of video. FIG. 28A is a block diagram showing a configuration of a recording apparatus PROD_C in which the above-described hierarchical video encoding apparatus 2 is mounted.

  As shown in (a) of FIG. 28, the recording device PROD_C includes an encoding unit PROD_C1 that obtains encoded data by encoding a moving image, and the encoded data obtained by the encoding unit PROD_C1 on the recording medium PROD_M. A writing unit PROD_C2 for writing. The hierarchical moving image encoding device 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: registration) For example, it may be loaded into a drive device (not shown) built in the recording device PROD_C.

  The recording device PROD_C is a camera PROD_C3 that captures moving images as a supply source of moving images to be input to the encoding unit PROD_C1, an input terminal PROD_C4 for inputting moving images from the outside, and reception for receiving moving images. The unit PROD_C5 and an image processing unit C6 that generates or processes an image may be further provided. In FIG. 28A, a configuration in which the recording apparatus PROD_C includes all of these is illustrated, 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 HDD (Hard Disk Drive) 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 or the image processing unit C6 is a main source of moving images), a smartphone (in this case In this case, the camera PROD_C3 or the receiving unit PROD_C5 is a main supply source of moving images) is also an example of such a recording device PROD_C.

  (B) of FIG. 28 is a block showing a configuration of a playback device PROD_D in which the above-described hierarchical video decoding device 1 is mounted. As shown in (b) of FIG. 28, 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 decoding the encoded data read by the read unit PROD_D1. And a decoding unit PROD_D2 to be obtained. The hierarchical moving image 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. 28B 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.

(About hardware implementation and software implementation)
Finally, each block of the hierarchical video decoding device 1 and the hierarchical video encoding device 2 may be realized in hardware by a logic circuit formed on an integrated circuit (IC chip), or may be a CPU (Central It may be realized by software using a Processing Unit).

  In the latter case, each of the devices includes a CPU that executes instructions of a control 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 A storage device (recording medium) such as a memory for storing various 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 in a computer-readable manner. This can also be achieved by supplying to each of the above devices and reading and executing the program code recorded on the recording medium by the computer (or CPU or MPU (Micro Processing Unit)).

  Examples of the recording medium include tapes such as magnetic tapes and cassette tapes, magnetic disks such as floppy (registered trademark) disks / hard disks, CD-ROM (Compact Disc Read-Only Memory) / MO (Magneto-Optical) / Disks including optical disks such as MD (Mini Disc) / DVD (Digital Versatile Disk) / CD-R (CD Recordable), cards such as IC cards (including memory cards) / 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 logic circuits such as PLD (Programmable Logic Device) and FPGA (Field Programmable Gate Array) Etc. 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, the Internet, an intranet, an extranet, a LAN (Local Area Network), an ISDN (Integrated Services Digital Network), a VAN (Value-Added Network), a CATV (Community Antenna Television) communication network, a virtual private network (Virtual Private Network), A telephone line network, a mobile communication network, a satellite communication network, etc. can be used. 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 is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention is suitable for a hierarchical image decoding device that decodes encoded data in which image data is hierarchically encoded, and a hierarchical image encoding device that generates encoded data in which image data is hierarchically encoded. Applicable to. Further, the present invention can be suitably applied to the data structure of hierarchically encoded data generated by the hierarchical image encoding device and referenced by the hierarchical image decoding device.

1. Hierarchical video decoding device (image decoding device)
11 NAL demultiplexing unit 12 Target layer picture decoding unit (image decoding device)
13 Reference layer picture decoding unit (image decoding device)
DESCRIPTION OF SYMBOLS 301 Variable length decoding part 302 Prediction parameter decoding part 303 Inter prediction parameter decoding part 304 Intra prediction parameter decoding part 320 Inter-layer information derivation part 306 Reference picture memory 307 Prediction parameter memory 308 Prediction image generation part 309 Inter prediction image generation part 310 Intra prediction Image generation unit 311 Inverse quantization / inverse DCT unit 312 Addition unit 314 Resampling unit 315 Inter-layer image mapping unit 3151 Reference pixel derivation unit 3152 Resampled image generation unit 316 Inter-layer motion mapping unit 3161 Reference image block derivation unit 3162 Motion information Generation unit 3020 Inter-layer information derivation unit 3031 Inter prediction parameter decoding control unit 3032 AMVP prediction parameter derivation unit 3035 Addition unit 3036 Merge prediction parameter derivation unit 30 61 Merge candidate derivation unit 30362 Merge candidate selection unit 303611 Merge candidate storage unit 303613 Basic merge candidate derivation unit 3036131 Spatial merge candidate derivation unit 3036132 Temporal merge candidate derivation unit 3036133 Join merge candidate derivation unit 3036134 Zero merge candidate derivation unit 3033 Vector candidate derivation unit 3034 Prediction vector selection unit 30331 Vector candidate storage unit 30332 Basic vector candidate derivation unit 303321 Spatial vector candidate derivation unit 303332 Time vector candidate derivation unit 303323 Zero vector candidate derivation unit 2 Hierarchical video encoding device (image encoding device)
21 NAL multiplexing unit 22 Target layer picture encoding unit 102 Subtraction unit 103 DCT / quantization unit 104 Variable length encoding unit 105 Inverse quantization / inverse DCT unit 106 Addition unit 108 Prediction parameter encoding unit 109 Reference picture memory 110 Encoding Parameter determining unit 111 Prediction parameter encoding unit 112 Inter prediction parameter encoding unit 113 Intra prediction parameter encoding unit 114 Reference layer corresponding region estimation unit 1121 Merge prediction deriving unit 1122 AMVP prediction parameter deriving unit 1123 Subtraction unit 1124 Inter prediction parameter encoding Control unit 1160 Inter-layer information deriving unit

Claims (13)

An image decoding device that decodes hierarchically encoded data in which image information relating to images of different quality for each layer is hierarchically encoded, and restores an image in a target layer to be decoded,
Reference layer corresponding region information decoding means for decoding reference layer corresponding region information indicating a corresponding region between the target layer and the reference layer;
Re-sampling means for generating a re-sampled reference layer picture by associating the image and motion information of the reference layer picture with the picture of the target layer based on the decoded reference layer picture and the reference layer corresponding region information;
Prediction image generation means for generating a prediction image of each prediction unit constituting the picture of the target layer,
The resampling means further includes reference pixel position deriving means for deriving a reference pixel position of a reference layer picture corresponding to each pixel of the resample reference layer picture,
Resampled image generation means for generating each pixel of the resample reference layer picture using a predetermined resample filter on a pixel on a filter region including the derived reference pixel position;
The moving picture decoding apparatus according to claim 1, wherein when the filter region includes coordinates outside the screen of the reference layer picture, the resampling image generation means replaces the coordinates with the screen edge closest to the reference layer picture. An image decoding device that decodes hierarchically encoded data in which image information relating to images of different quality for each layer is hierarchically encoded, and restores an image in a target layer to be decoded,
Reference layer corresponding region information decoding means for decoding reference layer corresponding region information indicating a corresponding region between the target layer and the reference layer;
Re-sampling means for generating a re-sampled reference layer picture by associating the image and motion information of the reference layer picture with the picture of the target layer based on the decoded reference layer picture and the reference layer corresponding region information;
A prediction image generating unit that generates a prediction image of each prediction unit constituting the picture of the target layer,
The prediction image generation means generates a prediction image of the prediction unit by inter-layer image prediction that does not satisfy the predetermined condition when the prediction method of the prediction unit is inter-layer image prediction. apparatus. The moving image decoding apparatus further includes an inter-layer image prediction constraint flag decoding unit that decodes an inter-layer image prediction constraint flag that prohibits inter-layer image prediction satisfying a predetermined condition,
When the inter-layer image prediction constraint flag is true and the prediction method of the prediction unit is inter-layer image prediction, the predicted image generation means performs prediction of the prediction unit by inter-layer image prediction that does not satisfy the predetermined condition. The moving image decoding apparatus according to claim 2, wherein a prediction image is generated.   The inter-layer image prediction satisfying the predetermined condition refers to (1) the left end of the corresponding region with respect to the corresponding region on the resample reference layer picture corresponding to the prediction unit and the reference layer corresponding region in the inter-layer image prediction. The coordinates are smaller than the left end coordinates of the reference layer corresponding area, (2) the right end coordinates of the corresponding area are larger than the right end coordinates of the reference layer corresponding area, and (3) the upper end coordinates of the corresponding area are the reference layer corresponding areas. 4. The case of satisfying at least one of (4) the lower end coordinate of the corresponding region being larger than the lower end coordinate of the reference layer corresponding region. The moving picture decoding apparatus described. The inter-layer image prediction satisfying the predetermined condition refers to (1) the right end of the corresponding region with respect to the corresponding region on the resample reference layer picture corresponding to the prediction unit and the reference layer corresponding region in the inter-layer image prediction. The coordinates are smaller than the left end coordinates of the reference layer corresponding area; (2) the left end coordinates of the corresponding area are larger than the right end coordinates of the reference layer corresponding area;
(3) The lower end coordinate of the corresponding region is smaller than the upper end coordinate of the reference layer corresponding region, and (4) the upper end coordinate of the corresponding region is larger than the lower end coordinate of the reference layer corresponding region, at least one of the above is satisfied. The moving picture decoding apparatus according to claim 2 or 3, wherein the moving picture decoding apparatus is a case.   5. The resampling unit generates only an image in the reference layer corresponding region among images of the resample reference layer picture when the inter-layer image prediction constraint flag is true. The moving picture decoding apparatus described in 1.   7. The moving picture decoding apparatus according to claim 3, wherein the inter-layer image prediction constraint flag decoding unit decodes the inter-layer image prediction constraint flag based on presence or absence of reference layer corresponding region information.   The reference layer corresponding region information decoding means decodes reference layer corresponding region information common to the entire target sequence in units of sequences, and decodes reference layer corresponding region information corresponding to each picture in units of pictures. The moving picture decoding apparatus according to claim 1.   9. The moving picture decoding apparatus according to claim 8, wherein the reference layer corresponding area information corresponding to each picture is difference information from the reference layer corresponding area information common to the entire target sequence. An inter-layer image prediction decoding means for decoding an inter-layer image prediction flag indicating whether the prediction method of the prediction unit is inter-layer image prediction;
6. The moving picture decoding apparatus according to claim 4, wherein the inter-layer image prediction decoding unit omits decoding of an inter-layer image prediction flag related to inter-layer image prediction that satisfies the predetermined condition. An image encoding apparatus that encodes hierarchical encoded data in which image information related to images of different quality for each layer is encoded hierarchically, and encodes an image in a target layer to be encoded,
Reference layer corresponding region information encoding means for encoding reference layer corresponding region information indicating a corresponding region between a target layer and a reference layer;
An inter-layer image prediction constraint flag encoding means for encoding an inter-layer image prediction constraint flag that prohibits inter-layer image prediction satisfying a predetermined condition;
Re-sampling means for generating a re-sampled reference layer picture by associating the image and motion information of the reference layer picture with the picture of the target layer based on the encoded reference layer picture and the reference layer corresponding region information;
A prediction image generating unit that generates a prediction image of each prediction unit constituting the picture of the target layer,
When the inter-layer image prediction constraint flag is true and the prediction method of the prediction unit is inter-layer image prediction, the predicted image generation means performs prediction of the prediction unit by inter-layer image prediction that does not satisfy the predetermined condition. A moving picture coding apparatus for generating a predicted picture.   The inter-layer image prediction satisfying the predetermined condition refers to (1) the left end of the corresponding region with respect to the corresponding region on the resample reference layer picture corresponding to the prediction unit and the reference layer corresponding region in the inter-layer image prediction. The coordinates are smaller than the left end coordinates of the reference layer corresponding area, (2) the right end coordinates of the corresponding area are larger than the right end coordinates of the reference layer corresponding area, and (3) the upper end coordinates of the corresponding area are the reference layer corresponding areas. The moving image according to claim 11, wherein the moving image satisfies at least one of the following: (4) the lower end coordinate of the corresponding region is larger than the lower end coordinate of the reference layer corresponding region. Encoding device. The inter-layer image prediction satisfying the predetermined condition refers to (1) the right end of the corresponding region with respect to the corresponding region on the resample reference layer picture corresponding to the prediction unit and the reference layer corresponding region in the inter-layer image prediction. The coordinates are smaller than the left end coordinates of the reference layer corresponding area; (2) the left end coordinates of the corresponding area are larger than the right end coordinates of the reference layer corresponding area;
(3) The lower end coordinate of the corresponding region is smaller than the upper end coordinate of the reference layer corresponding region, and (4) the upper end coordinate of the corresponding region is larger than the lower end coordinate of the reference layer corresponding region, at least one of the above is satisfied. The moving picture coding apparatus according to claim 11, wherein the moving picture coding apparatus is a case.