JP6224930B2 - Image decoding apparatus, image decoding method and image encoding apparatus - Google Patents

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 the information transmitted by the communication system or the information recorded in the storage device is an image or a moving image. Conventionally, techniques for encoding an image for transmission and storage of these images (hereinafter, including moving images) are known.

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

  In these moving picture coding methods, a predicted picture is usually generated based on a local decoded picture obtained by coding / decoding an input picture, and the predicted picture is obtained by subtracting it from the input picture (original picture). Prediction residuals (sometimes referred to as "difference images" or "residual images") are encoded. Further, as a method of generating a prediction image, inter-screen prediction (inter prediction) and intra-frame prediction (intra prediction) can be mentioned.

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

  In inter prediction, inter-picture motion compensation generates a predicted image. The decoded picture used for prediction image generation in inter prediction is called a reference picture.

  Also, in recent years, hierarchical coding techniques have been proposed for hierarchically coding images according to the required data rate. SHVC (Scalable HEVC) is known as one of the 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, in the upper layer, inter-layer prediction is performed 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 the decoded image of the lower layer. In inter-layer motion prediction, motion information prediction values are derived using motion information of lower layers.

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

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

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

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

"Recommendation H.265 (04/13)", ITU-T (released on 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: Inchon, KR, 18- 26 Apr. 2013 (released on June 14, 2013)

  In SHVC mentioned as the prior art, when generating a predicted image of a prediction unit PU on the target picture curPic by inter-layer image prediction, refer to an image outside the reference layer corresponding region on the resample reference layer picture rsPic. Can. That is, the predicted image of inter-layer image prediction can include pixels generated by padding on the resample reference layer picture rsPic. However, in inter-layer image prediction, there is a problem that the prediction image including pixels generated by padding has low prediction accuracy, which results in a decrease in coding efficiency and a decrease in image quality. Also, in the prior art, when generating a resample pixel at coordinates outside the reference layer corresponding area on the resample reference layer picture rsPic, the coordinate is replaced with the border pixel of the closest reference layer corresponding area. There is 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 thereof is to provide a mechanism for controlling the applicability of inter-layer image prediction with reference to pixels outside the reference layer corresponding region in the hierarchical coding method. It is to do. Another object of the present invention is to realize an image coding apparatus and an image decoding apparatus for coding / decoding coded data with less 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 an image of different quality for each layer is hierarchically encoded, and is an object to be decoded. An image decoding apparatus that restores an image in a layer,
Reference layer corresponding area information decoding means for decoding reference layer corresponding area information indicating the corresponding area of the target layer and the reference layer;
Resampling means for correlating 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 area information, and generating a resampled reference layer picture;
A prediction image generation unit configured to generate 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;
A resampling image generation unit configured to generate each pixel of the resampled reference layer picture by using a predetermined resampling filter for pixels on a filter area including the derived reference pixel position;
The resampling image generation means is characterized in that, when the off-screen coordinates of the reference layer picture are included in the filter region, the re-sampling image generation means replaces the coordinates of the closest screen edge of 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 area, the reference pixel position (xRef, yRef) on the reference layer picture is directly derived. . Therefore, the derivation process relating to the derivation of the reference pixel position can be simplified as compared to the prior art. 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 screen outside the screen is displayed in the filter area on the reference layer picture to which the resample filter is applied. If there is a pixel at a coordinate of {circumflex over (x)}, a resampled image is generated using a pixel having a high correlation (close in spatial distance) with the pixel. As a result, it is possible to improve the accuracy of the resampled image outside the reference layer corresponding area as compared with the prior art. In addition, with regard to inter-layer image prediction that refers to pixels outside the reference layer corresponding region, prediction accuracy can be improved more than in the related art. Therefore, it leads to the improvement of coding efficiency. In particular, according to the present invention, it is possible to generate a region where the pixel values of the resample image change smoothly in the region of width ΔFX and height ΔFY in the horizontal direction outside the boundary of the reference layer corresponding region. Therefore, in the inter-layer image prediction, the prediction accuracy of the 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 boundary of the reference layer corresponding region is improved. It can be done.

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 an image of different quality for each layer is hierarchically encoded, and is an object to be decoded. An image decoding apparatus that restores an image in a layer,
Reference layer corresponding area information decoding means for decoding reference layer corresponding area information indicating the corresponding area of the target layer and the reference layer;
Resampling means for correlating 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 area information, and generating a resampled reference layer picture;
A prediction image generation unit configured to generate a prediction image of each prediction unit constituting the picture of the target layer;
The prediction image generation means is characterized in that, when the prediction method of the prediction unit is inter-layer image prediction, the prediction image of the prediction unit is generated by inter-layer image prediction not satisfying a predetermined condition.

  As described above, according to the above configuration, based on the decoded reference layer picture and the reference layer corresponding area information, the image and motion information of the reference layer picture are associated with the picture of the target layer, and Since the image and motion information are generated, the accuracy of inter-layer image prediction and inter-layer motion prediction can be improved. As a result, code efficiency can be further improved. Further, according to the above configuration, since the use of the inter-layer image prediction that satisfies the predetermined condition with low prediction accuracy is prohibited, the coding 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 inhibits an inter-layer image prediction that satisfies a predetermined condition;
When the inter-layer image prediction restriction flag is true and the prediction method of the prediction unit is inter-layer image prediction, the predicted image generation means generates the inter-layer image prediction not satisfying the predetermined condition. Generating a predicted image.

  According to the above configuration, it is possible to control whether to inhibit inter-layer image prediction that satisfies the predetermined condition. In particular, when the inter-layer image prediction restriction flag is true, the use of the inter-layer image prediction which satisfies a predetermined condition with low prediction accuracy is prohibited, so that the coding efficiency can be improved.

  Furthermore, in the image decoding device according to the present invention, the inter-layer image prediction satisfying the predetermined condition corresponds to a corresponding region on the resample reference layer picture corresponding to the prediction unit and the reference layer in inter-layer image prediction. Regarding the area, (1) the left end coordinate of the corresponding area is smaller than the left end coordinate of the reference layer corresponding area, (2) the right end coordinate of the corresponding area is larger than the right end coordinate of the reference layer corresponding area, (3) the correspondence The upper end coordinate of the area is smaller than the upper end coordinate of the reference layer corresponding area, and (4) the lower end coordinate of the corresponding area satisfies at least one of the lower end coordinates of the reference layer corresponding area. It features.

  As described above, according to the above configuration, it is possible to prohibit the use of inter-layer image prediction that refers to an image outside the reference layer corresponding region. Therefore, since the inter-layer image prediction which refers to the pixel outside the reference layer corresponding area with low prediction accuracy is not used, it is possible to realize an image decoding apparatus with higher coding efficiency. Furthermore, according to the above configuration, when the inter-layer image prediction restriction flag is decoded, if the flag is true, an image outside the reference layer corresponding region on the resample reference layer picture in the target sequence (reference layer Since it is known that “outside the corresponding region” is not referred to at the time of inter-layer image prediction, generation of an image outside the reference layer corresponding region can be omitted when generating a resampled image of the resample reference layer picture.

  Furthermore, in the image decoding device according to the present invention, the inter-layer image prediction satisfying the predetermined condition corresponds to a corresponding region on the resample reference layer picture corresponding to the prediction unit and the reference layer in inter-layer image prediction. Regarding the area, (1) the right end coordinate of the corresponding area is smaller than the left end coordinate of the reference layer corresponding area, (2) the left end coordinate of the corresponding area is larger than the right end coordinate of the reference layer corresponding area, (3) the correspondence The lower end coordinates of the area are smaller than the upper end coordinates of the reference layer corresponding area, and (4) the upper end coordinates of the corresponding area satisfy at least one of the lower end coordinates of the reference layer corresponding area. It features.

  As described above, according to the above configuration, it is possible to prohibit use of inter-layer image prediction that refers to only an image outside the reference layer corresponding region. Therefore, since the inter-layer image prediction that refers only to the pixels outside the reference layer corresponding area with low prediction accuracy is not used, it is possible to realize an image decoding apparatus with higher coding efficiency.

  Furthermore, in the image decoding device according to the present invention, when the inter-layer image prediction restriction flag is true, the resampling means only the image within the reference layer corresponding region among the images of the resample reference layer picture. To generate.

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

  Further, in the image decoding apparatus according to the present invention, the inter-layer image prediction restriction flag decoding unit is characterized in that the inter-layer image prediction restriction flag is decoded based on the presence or absence of reference layer corresponding area information.

  As described above, according to the above configuration, the inter-layer image prediction restriction flag is explicitly decoded only when there is reference layer correspondence information. That is, when there is no reference layer corresponding area information, decoding of the inter-layer image prediction restriction flag is omitted. Therefore, the processing relating to the decoding of the inter-layer image prediction restriction flag can be reduced, and furthermore, the code amount can be reduced.

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

  As described above, according to the above-described configuration, it is possible to use the inter-layer correspondence relationship 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 correspondence area. 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 resampling filter to the reference pixel and the peripheral pixels. . Thereby, the effect of improving the accuracy of the resampled image used in the inter-layer image prediction can be obtained. In particular, for a sequence in which the correspondence area between the target layer and the reference layer changes in units of pictures, inter-layer image mapping is performed based on the inter-layer correspondence relationship parameter derived by the reference layer correspondence area information. By performing the inter-layer image mapping based on the inter-layer correspondence parameter derived by the reference layer corresponding area information in units of pictures, the effect of further improving the accuracy of the resampled image used in the inter-layer image prediction can be achieved. . Along with this, the prediction accuracy of the inter-layer image prediction is also improved, so that the coding efficiency can be improved.

  Further, according to the above configuration, the inter-layer correspondence relationship parameter (Offset L, Offset T, Offset R, etc.) between the target layer (for example, the enhancement layer) and the reference layer (for example, the base layer) is derived based on the reference layer correspondence information. The reference image block on the reference layer picture corresponding to the target block on the resample reference layer picture is determined based on the OffsetB, SRLPW, SRLPH, ScaleFactor X, ScaleFactor Y, etc.), and the target block is determined based on the motion information of the reference image block. Motion information can be generated. As a result, it is possible to obtain an effect of improving the accuracy of motion information (temporal motion information) used in inter-layer motion prediction. In particular, for a sequence in which the corresponding region of the target layer and the reference layer changes in units of pictures, motion mapping between layers is performed based on the inter-layer correspondence relationship parameter derived by the reference layer corresponding region information. By performing inter-layer motion mapping based on inter-layer correspondence relationship parameters derived from active reference layer corresponding region information (reference layer corresponding region information in units of pictures), motion information (temporal used more in inter-layer motion prediction) The effect of improving the accuracy of motion information) is achieved. Along with this, the prediction accuracy of the inter-layer motion prediction is also improved, so that the coding efficiency can be improved.

  Further, in the image decoding apparatus according to the present invention, the reference layer corresponding area information corresponding to each picture is difference information from reference layer corresponding area information common to the entire target sequence.

  As described above, according to the above configuration, compared to the case of explicitly notifying the information of the reference layer corresponding area in the picture unit, the picture for the reference layer corresponding area common to the whole sequence in the reference layer corresponding area information in the picture unit. By notifying the difference information of the size of the reference layer corresponding area of the unit, it is possible to reduce the code amount necessary for decoding the reference layer corresponding area information of the picture unit.

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 scheme of the prediction unit is inter-layer image prediction.
The inter-layer image prediction decoding means is characterized in that the decoding of the inter-layer image prediction flag related to the inter-layer image prediction satisfying the predetermined condition is omitted.

  As described above, according to the above configuration, it is possible to control whether or not the inter-layer image prediction flag corresponding to the target prediction unit is explicitly decoded. That is, in the case of inter-layer image prediction satisfying the above predetermined conditions in the target prediction unit, 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 involved in the decoding of the prediction flag can be reduced. In addition, since the code amount related to the inter-layer image prediction flag can be reduced, the code efficiency can be improved.

In order to solve the above problems, an image coding apparatus according to the present invention codes hierarchically encoded data in which image information relating to an image of a quality different for each layer is hierarchically encoded, to be encoded. An image coding apparatus for coding an image in a target layer
Reference layer corresponding area information encoding means for encoding reference layer corresponding area information indicating the corresponding area of the target layer and the reference layer;
An inter-layer image prediction constraint flag encoding unit that encodes an inter-layer image prediction constraint flag that prohibits an inter-layer image prediction that satisfies a predetermined condition;
Resampling means for correlating 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 reference layer corresponding area information, and generating a resampled reference layer picture;
A prediction image generation unit configured to generate a prediction image of each prediction unit constituting the picture of the target layer;
When the inter-layer image prediction restriction flag is true and the prediction method of the prediction unit is inter-layer image prediction, the predicted image generation means generates the inter-layer image prediction not satisfying the predetermined condition. A moving image coding apparatus characterized by generating a predicted image.

  According to the above configuration, based on the encoded reference layer picture and the reference layer corresponding area information, the image and motion information of the reference layer picture are associated with the picture of the target layer to resample the reference layer picture The inter-layer image prediction and the inter-layer motion prediction accuracy can be improved by generating the image and the motion information. As a result, code efficiency can be further improved. Further, according to the above configuration, since the use of the inter-layer image prediction that satisfies the predetermined condition with low prediction accuracy is prohibited, the coding efficiency can be improved.

  Furthermore, in the image coding apparatus according to the present invention, the inter-layer image prediction satisfying the predetermined condition is the corresponding region on the resample reference layer picture corresponding to the prediction unit and the reference layer in the inter-layer image prediction. Regarding the corresponding area, (1) the left end coordinate of the corresponding area is smaller than the left end coordinate of the reference layer corresponding area, (2) the right end coordinate of the corresponding area is larger than the right end coordinate of the reference layer corresponding area, The upper end coordinate of the corresponding area is smaller than the upper end coordinate of the reference layer corresponding area, and (4) the lower end coordinate of the corresponding area is larger than the lower end coordinate of the reference layer corresponding area. 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 to an image outside the reference layer corresponding region. Therefore, since the inter-layer image prediction which refers to the pixel outside the reference layer corresponding area with low prediction accuracy is not used, it is possible to realize an image coding apparatus with higher coding efficiency. Furthermore, according to the above configuration, when the inter-layer image prediction restriction flag is determined, if the flag is true, an image outside the reference layer corresponding region on the resample reference layer picture in the target sequence (reference layer Since it is known that “outside the corresponding region” is not referred to at the time of inter-layer image prediction, generation of an image outside the reference layer corresponding region can be omitted when generating a resampled image of the resample reference layer picture.

  Furthermore, in the image coding apparatus according to the present invention, the inter-layer image prediction satisfying the predetermined condition is the corresponding region on the resample reference layer picture corresponding to the prediction unit and the reference layer in the inter-layer image prediction. Regarding the corresponding area, (1) the right end coordinate of the corresponding area is smaller than the left end coordinate of the reference layer corresponding area, (2) the left end coordinate of the corresponding area is larger than the right end coordinate of the reference layer corresponding area, (3) above The lower end coordinates of the corresponding area are smaller than the upper end coordinates of the reference layer corresponding area, and (4) the upper end coordinates of the corresponding area satisfy at least one of the lower end coordinates of the reference layer corresponding area. It is characterized by

  As described above, according to the above configuration, it is possible to prohibit use of inter-layer image prediction that refers to only an image outside the reference layer corresponding region. Therefore, since the inter-layer image prediction that refers only to the pixels outside the reference layer corresponding area with low prediction accuracy is not used, it is possible to realize an image coding apparatus with higher coding efficiency.

  As described above, in the image decoding device according to the present invention, when the inter-layer image prediction restriction flag indicates that the inter-layer image prediction referencing the pixels outside the reference layer corresponding region is not applicable, the reference layer correspondence region having low prediction accuracy Since the inter-layer image prediction that refers to the outer pixels is not used, an effect of improving the code efficiency is obtained. In addition, when generating the image rsPicSample of the resample reference picture rsPic, the processing (padding processing) for generating the pixels outside the reference layer corresponding area can be omitted, so that the processing amount related to the resampling processing can be reduced. Play.

  As described above, in the image coding apparatus according to the present invention, when the inter-layer image prediction restriction flag indicates that the inter-layer image prediction referencing the pixels outside the reference layer corresponding region is not applicable, the reference layer Since inter-layer image prediction that refers to pixels outside the region is not used, an effect of improving code efficiency is obtained. In addition, when generating the image rsPicSample of the resample reference picture rsPic, the processing (padding processing) for generating the pixels outside the reference layer corresponding area can be omitted, so that the processing amount related to the resampling processing can be reduced. Play.

It is a figure for demonstrating the layer structure of hierarchy coding data which concerns on embodiment of this invention, Comprising: (a) is shown about the hierarchy moving image encoding device side, (b) is hierarchy moving image decoding. It shows about the apparatus side. It is a figure for demonstrating the structure of the hierarchy coding data which concerns on embodiment of this invention, Comprising: (a) is a sequence layer which defines sequence SEQ, (b) is a picture layer which prescribes picture PICT, c) slice layer defining slice S, (d) slice data layer defining slice data, (e) coding tree layer defining coding tree unit included in slice data (f Is a diagram illustrating a coding unit layer that defines coding units (CUs) 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) of the image of an object layer, and the image of a reference layer. It is an example of reference layer corresponding area information and an inter-layer image prediction restriction flag according to the present embodiment. 15 is an example of inter-layer image prediction that refers to an image outside the reference layer corresponding area SRLA. (A) shows the case where both the reference layer corresponding area SRLA and the reference layer corresponding area NSRLA are referred to at the time of inter-layer image prediction, and (b) shows the reference layer corresponding area at the time of inter-layer image prediction The case where only the image of the external NSRLA is referred to is shown. It is an example of active reference layer designation information and active reference layer corresponding area information according to the present embodiment. It is another example of the active reference layer corresponding | compatible area | region 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 an object block of an object block, a space motion vector, and an object block of 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 resampling 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 showing a schematic structure of a hierarchy video coding device concerning one embodiment of the present invention. It is a functional block diagram showing a schematic structure of an image coding device concerning this embodiment. It is a functional block diagram showing a schematic structure of an inter prediction parameter coding part concerning 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 transmission apparatus carrying the said hierarchy moving image encoding apparatus, and the receiving apparatus carrying the said hierarchy moving image decoding apparatus. (A) shows a transmitter equipped with a hierarchical video coding device, and (b) shows a receiver equipped with a hierarchical video decoding device. It is a figure showing composition of a recording device carrying the above-mentioned hierarchy video coding device, and a reproduction device carrying the above-mentioned hierarchy video decoding device. (A) shows a recording apparatus equipped with a hierarchical moving picture coding apparatus, and (b) shows a reproduction apparatus equipped with a hierarchical moving picture decoding apparatus. 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 the non-reference layer corresponding area | region on the resample reference layer picture rsPic, and (a) is an example of derivation of the reference pixel position based on prior art. b) is an example of derivation of the reference pixel position according to the present invention. It is a figure for demonstrating the resample pixel of NSRLA out of the reference layer corresponding area on 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 | region information which concerns on this embodiment. It is another example of the active reference layer corresponding | compatible area | region information which concerns on this embodiment. It is another example of the active reference layer corresponding | compatible area | region information which concerns on this embodiment.

The hierarchical video decoding device 1 and the hierarchical video encoding device 2 according to an embodiment of the present invention will be described below based on FIGS. 1 to 28.

〔Overview〕
The hierarchical moving image decoding apparatus (image decoding apparatus) 1 according to the present embodiment decodes encoded data hierarchically encoded by the hierarchical moving image encoding apparatus (image encoding apparatus) 2. Hierarchical coding is a coding scheme that hierarchically encodes moving images from low to high quality. Hierarchical coding is standardized, for example, in SVC and SHVC. In addition, the quality of a moving image here means the element which influences the appearance of a subjective and objective moving image widely. The quality of a moving image includes, for example, “resolution”, “frame rate”, “image quality”, and “pixel representation accuracy”. Therefore, hereinafter, when the quality of the moving image is different, it means that the “resolution” and the like are different as an example, but it is not limited thereto. For example, in the case of a moving picture quantized by different quantization steps (that is, in the case of a moving picture encoded by different coding noise), it can be said that the quality of the moving picture differs from each other.

  In addition, hierarchical coding technology is used for (1) spatial scalability, (2) temporal scalability, (3) signal to noise ratio (SNR) scalability, and (4) view scalability in terms of types of information to be hierarchically arranged. It may be classified. Spatial scalability is a technology for layering in resolution and image size. Temporal scalability is a technique for layering at a frame rate (the number of frames per unit time). SNR scalability is a technique for layering in coding noise. In addition, view scalability is a technology for hierarchizing at a viewpoint position associated with each image.

  Prior to detailed description of the hierarchical moving image encoding device 2 and the hierarchical moving image decoding device 1 according to the present embodiment, first (1) generated by the hierarchical moving image encoding device 2 and decoded by the hierarchical moving image decoding device 1 The layer structure of the encoded layer data 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, encoding and decoding of hierarchically encoded data will be described using FIG. 1 as follows. FIG. 1 is a view schematically showing a case where a moving image is hierarchically encoded / decoded in three layers, that is, 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 layer (or a decoded image corresponding to a specific layer) (e.g. Decoded image POUT # A).

  FIG. 1A shows hierarchical moving picture coding devices 2 # A to 2 # C that hierarchically encode input images PIN # A to PIN # C and generate encoded data DATA # A to DATA # C, respectively. Is shown. FIG. 1 (b) is a hierarchical moving image decoding device 1 # A ̃ that decodes encoded data DATA # A ̃DATA # C hierarchically encoded to generate decoded images POUT # A ̃POUT # C, respectively. 1 # C is shown.

  First, the encoding device side will be described using FIG. 1 (a). The input images PIN # A, PIN # B, and PIN # C, which are inputs on the encoding device side, are the same as the original images but have different image quality (resolution, frame rate, image quality, etc.). The quality of the image decreases in the order of the input image PIN # A, PIN # B, and PIN # C.

  The hierarchical moving image coding device 2 # C of the lower layer L3 encodes the input image PIN # C of the lower layer L3 to generate encoded data DATA # C of the lower layer L3. Basic information necessary to decode 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 lowermost layer, the encoded data DATA # C of the lower layer L3 is also referred to as basic encoded data.

  Also, the hierarchy video coding device 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 the middle hierarchy L2 is generated. To generate encoded data DATA # B of In addition to the basic information “C” included in the encoded data DATA # C, the encoded data DATA # B of the intermediate layer L2 additionally includes the additional information necessary to decode the decoded image POUT # B of the intermediate layer. Information (indicated by "B" in FIG. 1) is included.

  Also, the layer moving picture coding device 2 # A of the upper layer L1 encodes the input image PIN # A of the upper layer L1 with reference to the encoded data DATA # B of the middle layer L2, and The encoded data DATA # A is generated. In the encoded data DATA # A of the upper layer L1, 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 are to be decoded. In addition to the necessary additional information "B", the additional information (indicated by "A" in FIG. 1) necessary to decode the upper layer decoded image POUT # A is included.

  Thus, the encoded data DATA # A of the upper layer L1 includes information on decoded images of a plurality of different qualities.

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

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

  For example, the hierarchy decoding device 1 # B of the middle hierarchy L2 is information required to decode the decoded image POUT # B from the hierarchy coding data DATA # A of the upper hierarchy L1 (that is, hierarchy coding data DATA # "B" and "C" included in A may be extracted to decode the decoded image POUT # B. In other words, on the decoding device side, the decoded images POUT # A, POUT # B, and POUT # C can be decoded based on the information included in the layer encoded data DATA # A of the upper layer L1.

  The above is not limited to the above-described three-layer hierarchical encoding data, and the hierarchical encoding data may be hierarchically encoded in two hierarchical layers, or may be hierarchically encoded in more layers than three hierarchical layers. Good.

  Also, part or all of the encoded data relating to the decoded image of a specific layer may be encoded independently of the other layers, and there is no need to refer to information of other layers when decoding the specific layer. Layer encoded data may be configured as follows. For example, in the example described above with reference to FIGS. 1A and 1B, the decoding of the decoded image POUT # B is described with reference to “C” and “B”, but is not limited thereto. It is also possible to construct hierarchically encoded data so that the decoded image POUT # B can be decoded using only "B". For example, it is also possible to configure a hierarchical moving image decoding apparatus in which hierarchically encoded data consisting of only “B” and decoded image POUT # C are input for decoding of 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 then the image quality of the decoded images POUT # A, POUT # B, and POUT # C is different. It is also possible to generate hierarchically encoded data such that In that case, the hierarchical moving image coding apparatus of the lower layer generates hierarchically coded data by quantizing the prediction residual using a larger quantization width compared to the hierarchical moving image coding apparatus of the upper layer. 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 noted.

  Upper layer: A layer located above a certain layer is called an upper layer. For example, in FIG. 1, the upper layer of the lower layer L3 is the middle layer L2 and the upper layer L1. Further, the decoded image of the upper layer refers to a decoded image of higher quality (eg, high resolution, high frame rate, high image quality, etc.).

  Lower layer: A layer located lower than a certain layer is called 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. Also, the lower layer decoded image refers to a lower quality decoded image.

  Target layer: A layer that is subject to 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 layer of the upper layer L1 is the middle layer L2 and the lower layer L3. However, the present invention is not limited to this, and it is also possible to configure hierarchically-coded data so that it is not necessary to refer to all the lower layers in decoding of a specific above-mentioned layer. For example, the layer encoded data may be configured such that the reference layer of the upper layer L1 is either the middle layer L2 or the lower layer L3.

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

  Enhancement layer: The layer above the base layer is called the enhancement layer.

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

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

  Inter-layer prediction: Inter-layer prediction is based on syntax element values included in layer representations of layers (reference layers) different from the layer representation of the target layer, values derived from syntax element values, and decoded images. It is to predict syntax element values of the target layer, coding parameters used for decoding the target layer, and the like. Inter-layer prediction in which information on motion prediction is predicted from information on a reference layer may be referred to as inter-layer motion information prediction. In addition, inter-layer prediction to be predicted from the decoded image of the lower layer may be referred to as inter-layer image prediction (or inter-layer texture prediction). The layer used for inter-layer prediction is, for example, a lower layer of the target layer. Also, performing prediction in a target layer without using a reference layer may be referred to as intra-layer prediction.

  The above terms are for convenience of explanation until they get bored, and the above technical matters may be expressed in other terms.

[About the data structure of hierarchical coding data]
Hereinafter, the case of using HEVC and its extended method will be exemplified as a coding method for generating coded data of each layer. However, the present invention is not limited to this, and encoded data of each layer may be generated by an encoding method such as MPEG-2 or H.264 / AVC.

  Also, the lower layer and the upper layer may be encoded by different encoding schemes. Also, the encoded data of each layer may be supplied to the layer moving picture decoding device 1 through different transmission paths, or may be supplied to the layer moving picture decoding device 1 through the same transmission path. .

  For example, when super-high definition video (moving image, 4K video data) is scalable encoded and transmitted by the base layer and one enhancement layer, the base layer downscales 4K video data and interlaced video data The MPEG-2 or H.264 / AVC may be encoded and transmitted over a television broadcast network, and the enhancement layer may encode 4K video (progressive) according to HEVC, and may be transmitted over the Internet.

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

The hierarchical structure of data in the hierarchical encoding data DATA is shown in FIG. Hierarchical encoded data DATA illustratively includes a sequence and a plurality of pictures forming the sequence.
(A) to (f) of FIG. 2 are respectively a sequence layer defining the sequence SEQ, a picture layer defining the picture PICT, a slice layer defining the slice S, a slice data layer defining slice data, and slice data. FIG. 10 is a diagram illustrating a coding tree layer that defines a coding tree unit (CTU) to be included, and a coding unit layer that defines a coding unit (coding unit (CU)) that is included in a coding tree unit CTU. .

(Sequence layer)
In the sequence layer, a set of data to which the hierarchical moving image decoding device 1 refers in order to decode a 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, and Supplemental enhancement information SEI (Supplemental Enhancement Information) is included. Here, the value shown after # indicates a layer ID. Although FIG. 2 shows an example in which coded data of # 0 and # 1, that is, layer 0 and layer 1 exist, the type of layer and the number of layers are not limited thereto.

  A video parameter set VPS is a set of coding parameters common to a plurality of moving pictures and a set of coding parameters related to the plurality of layers included in the moving picture and each layer in a moving picture composed of a plurality of layers. A set is defined. An example of the 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 shown in SYNVPS01 in FIG. 3 (a). Further, in the VPS extended data (SYN VPS 02 in FIG. 3A), layer identifier specification information layer_id_nuh [i] (SYN VPS 03 in FIG. SYNS_VPS (b) that associates the layer identifier layer_id defined on the NAL unit header with the layer i. )including. Hereinafter, in order to simplify the description, it is assumed that the layer i represents a layer having a layer identifier layer_id = i unless otherwise noted. Further, in the VPS extended data (SYNVPS 02 in FIG. 3A), reference layer designation information (SYNVPS 04 in FIG. 3B) defining a reference layer which is a layer other than the target layer referred to in the target layer is included. Be Specifically, the layer dependency flag direct_dependency_flag [i] [j] is included in the reference layer specification information. If the layer dependency flag direct_dependency_flag [i] [j] has a value of 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 (also referred to as inter-layer prediction reference layer number) 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] [], which is a layer to which the target layer i refers, is derived. RefLayerId [i] [] is a list storing layer IDs of reference layers to which the target layer i refers, and has NumDirectRefLayers [i] elements. Further, when the layer dependency flag direct_dependency_flag [i] [j] is 1, the layer dependency type direct_dependency_type [i] [j] (SYNVPS 05 in FIG. 3B) is further included in the VPS. The layer dependency type direct_dependency_type [i] [j] has (1) an inter-layer image prediction presence / absence flag SamplePredEnableFlag [i] [j], (2) indicating whether or not the target layer i refers to the reference layer j. Inter-layer motion prediction presence / absence flag MotionPredEnableFlag [i] [j] indicating presence / absence of inter-layer motion prediction in which target layer i refers to reference layer j, (3) Reference layer referenced by target layer i for inter-layer image prediction (Also referred to as inter-layer image prediction reference layer number) NumSamplePredRefLayers [i], and (4) number of reference layers that the target layer i refers to for inter-layer motion prediction (also referred to as inter-layer motion prediction reference layer number) It is a syntax used to derive parameters such as NumMotionPredRefLayers [i]. Here, the inter-layer image prediction presence / absence flag SamplePredEnableFlag [i] [j] indicating the presence or 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) If is true, it indicates that there is inter-layer image prediction in which the target layer i refers to the reference layer j, and if the value is false, it indicates that there is no inter-layer image prediction.

SamplePredEnableFlag [i] [j] = ((direct_dependency_type [i] [j] + 1) &1); (F-1)
Further, the inter-layer motion prediction presence flag MotionPredEnableFlag [i] [j] indicating the presence or absence of inter-layer motion prediction in which the target layer i refers to the reference layer j is derived, for example, by the following formula (F-2), and the value is If true, it indicates that there is inter-layer motion prediction in which the target layer i refers to the reference layer j, and if 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)
Also, the inter-layer image prediction reference layer number 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.

  In addition, the inter-layer image prediction reference layer index SamplePredRefLayerId [i] for specifying the layer identifier of the reference layer used in the inter-layer image prediction in each layer based on the inter-layer image prediction presence / absence flag SamplePredEnableFlag [i] [j]. Inter-layer motion prediction reference layer index for specifying a layer identifier of a reference layer used in inter-layer motion prediction in each layer based on [sIdx] and inter-layer motion prediction presence / absence flag MotionPredEnableFlag [i] [j] 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 coding parameters to be referred to by the hierarchical moving image decoding device 1 for decoding the target sequence is defined. For example, the horizontal width PW and the vertical width PH of the pictures in the target sequence are defined. Further, the SPS defines reference layer corresponding area information indicating which area on the target picture curPic (or resample reference layer picture rsPic) of the target layer corresponds to the reference layer picture rlPic. Also, a plurality of SPSs may exist in the encoded data. In that case, an SPS to be used for decoding is selected from a plurality of candidates for each target sequence. The SPS used to decode a particular sequence is also referred to as the active SPS. In the following, unless otherwise noted, it means active SPS for the target sequence.

  Here, prior to the description of the reference layer corresponding area information, the corresponding area (reference layer corresponding area) of 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 picture (reference layer picture) of a reference layer having an image size of vertical width RLPH and horizontal width RLPW. In the drawing, rsPic is a picture (resample reference layer picture) rsPic in which the reference layer picture rlPic is mapped to the picture of the target layer having the image size of the vertical width PH and the horizontal width PW. SRLA (gray part) in the figure is an area (reference layer corresponding area) corresponding to the reference layer picture rlPic on the picture of the target layer, and has the size of the vertical width SRLPH and the horizontal width SRLPW. NSRLA on the same figure is an area outside the reference layer corresponding area SRLA (referred to as “outside of reference layer corresponding area”). Offset L on the same figure represents the offset in the horizontal direction (x direction) between the top left pixel of the reference layer corresponding area SRLA and the top left pixel of the picture of the target layer (or resample reference picture rsPic). OffsetT in the same figure represents the offset in the vertical direction (y direction) between the top left pixel of the reference layer corresponding area SRLA and the top left pixel of the picture of the target layer (or resample reference picture rsPic). OffsetR in the figure represents the offset in the horizontal direction (x direction) between the lower rightmost pixel of the reference layer corresponding area SRLA and the lowermost right pixel of the picture of the target layer (or resample reference picture rsPic). OffsetB in the figure indicates an offset in the vertical direction (y direction) between the lower rightmost pixel of the reference layer corresponding area SRLA and the lowermost right pixel of the picture of the target layer (or resample reference picture rsPic).

  The SPS includes SPS extension data sps_extension () shown in SYNSPS01 in FIG. 5 (a). Furthermore, the SPS extension data sps_extension () includes syntax groups indicated as SYNSPS02 in FIG. 5B as reference layer corresponding area information. The reference layer corresponding area information included in the SPS is a reference layer corresponding area which is common (reference) to the entire sequence. When the reference layer corresponding area changes for each picture, the 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 area information group presence / absence flag) indicating presence / absence of reference picture corresponding area information of the target picture curPic of the target layer curLayerId and the number of reference layers NumDirectRefLayers [curLayerId], and when the value is true, reference It indicates that there are several layers of reference layer corresponding area information, and if the value is false, it indicates that there is no reference layer corresponding area information. In the example of SYNSPS02 in FIG. 5B, when NumDirectRefLayers [curLyaerId] is larger 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 zero. In the prior art, although the reference layer number NumDirectRefLayers [curLayer] of the target layer is known, the syntax num_scaled_ref_layer_offsets explicitly indicating how many reference layer corresponding area information exists is included. The On the other hand, in the present invention, when the reference layer corresponding area information group presence / absence flag is true, the reference layer corresponding area information (NumDirectRefLayers [curLyaerId] pieces of reference layer corresponding area information) of each reference layer is explicitly notified. . By this, it is possible to reduce the code amount related to the reference layer corresponding area information as compared with the prior art in which the syntax num_scaled_ref_layer_offsets indicating the number of reference layer corresponding area information is notified.

  The configuration of SYNSPS 02A shown in FIG. 33 (a) may be used instead of SYNSPS02 in FIG. 5 (b). That is, when NumDirectRefLayers [curLyaerId] is larger than 1, the reference layer corresponding area information group presence / absence flag is explicitly notified, and when NumDirectRefLayers [curLyaerId] is 0, the reference layer corresponding area information group presence / absence flag is estimated to be 0 If NumDirectRefLayers [curLyaerId] is 1 (if NumDirectRefLayrs [curlayerId] is less than 2), the reference layer corresponding area information presence / absence flag is estimated to be 1. By this, compared with the example of SYNSPS02 in FIG. 5B, when the number of reference layers is one, it is not necessary to explicitly notify the reference layer corresponding area information group presence / absence flag, and reference layer corresponding area information group It is possible to reduce the amount of code related to the presence / absence flag. Also, 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 area information group presence / absence flag may be estimated to be zero.

  In the configuration of FIG. 33A described above, when NumDirectRefLayers [curLyaerId] is larger than 1, it is not necessary to encode reference layer correspondence area information by notifying the reference layer correspondence area information group presence / absence flag. And the amount of code can be reduced. Also, as described later, by not encoding the reference layer corresponding area information presence 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] is used. ] Can be reduced. Also, the configuration of SYNSPS 02B shown in FIG. 33 (b) may be used. In this case, the reference layer corresponding area information group presence / absence flag is not included, and the NumDirectRefLayers [curLayer] pieces of reference layer corresponding area information are explicitly notified. Similarly, it is possible to reduce the code amount related to the reference layer corresponding area information as compared with the prior art in which the syntax num_scaled_ref_layer_offsets indicating the number of reference layer corresponding area information is notified.

  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 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 as reference layer corresponding area information, and the above four cases are false. Each syntax value is estimated to be zero. The definition of each syntax is as follows. When the value of the reference layer corresponding area information group presence / absence flag is false, the value of the reference layer corresponding area information presence / absence flag is estimated to be zero.

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

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

  scaled_ref_layer_right_offset [i] is the lower rightmost pixel of the reference layer corresponding area SRLA on the resampled i-th reference layer RefLayerId [curLayerId] [i] and the lower rightmost luminance pixel of the target picture curPic used for inter-layer prediction Offset in the horizontal direction (x direction) between predetermined pixel units.

  scaled_ref_layer_bottom_offset [i] is between the lower rightmost pixel of the reference layer corresponding area SRLA on the resampled i-th reference layer RefLayerId [curLayerId] [i] and the lower rightmost pixel of the target picture curPic, which is used for inter-layer prediction The offset in the vertical direction (y direction) of the predetermined pixel unit.

  Therefore, when the reference layer corresponding area information presence / absence flag is 0, it is possible to reduce the code amount 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]). .

  The offsets OffsetL, OffsetT, OffsetR, and OffsetB in FIG. 4 are the syntax scaled_ref_layer_left_offset [dRlIdx], scaled_ref_layer_top_offset [dRlIdx] included in the reference layer corresponding area information between the target layer curLayerId and the reference layer RefLayerId [curLayerId] [dRlIdx]. The following equations (G-1) to (G-4) are derived using scaled_ref_layer_right_offset [dRlIdx] and scaled_ref_layer_bottom_offset [dRlIdx].

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 by a logarithmic value with 2 as a base. For example, in the case of using 2 pixels as a unit, sample_unit_bit = 1. When 2 ^ N pixels (where the value of N is 0 or more) are taken as a unit, sample_unit_bit = N. Sample_unit_bit may be determined in advance between the image decoding apparatus and the image encoding apparatus, or may be notified in a parameter set such as SPS. Note that OffsetL is also referred to as ScaledRefLayerLeftOffset, OffsetT as ScaledRefLayerTopOffset, OffsetR as ScaledRefLayerRightOffset, and OffsetB as ScaledRefLayerBottomOffset.

  Conversely, the value 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] corresponds to the reverse process of (G-1) to (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)
In addition, the value of scaled_ref_layer_offset_present_flag [dRlIdx] is set to 0 when all the syntax values determined by Equations (I-1) to (I-4) are 0, and is set to 1 otherwise. .

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

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

  Also, the size ratio ScaleFactor X of the width of the reference layer picture rlPic to the width of the reference layer corresponding area SRLA in FIG. 4 and the size ratio ScaleFactorY of the width of the reference layer picture rlPic to the height of the reference layer corresponding area SRLA are as follows: It derives from the formulas (G-7) to (G-8).

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

(About the inter-layer image prediction restriction 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. The inter-layer image prediction constraint flag inter_layer_sample_pred_constraint_flag is an inter-layer image that refers to an image outside the reference layer corresponding area SRLA on the resample reference layer picture rsPic in all prediction units PBX on the target picture curPic when the value is true. Indicates that the use of prediction is prohibited, and if the value is false, an inter-layer that refers to an image outside the reference layer corresponding area SRLA on the resample reference layer picture rsPic in all prediction blocks PBX on the target picture curPic Indicates that the use of image prediction is permitted.

  Further, whether or not the inter-layer image prediction restriction flag is explicitly included in the SPS extension data is determined based on a flag ScaledRefLayerOffsetsPresentFlag indicating that at least one reference layer corresponding area information shown in SYNSPS 02 in FIG. 5 is included. ScaledRefLayerOffsetsPresentFlag is derived by logical OR with the value of the reference layer corresponding area presence flag of each layer.

ScaledRefLayerOffsetsPresentFlag | = scaled_ref_layer_present_flag [i];
If 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. If false, it is not included in the SPS extension data, and the value is estimated to be false (0).

  Note that ScaledRefLayerOffsetsPresentFlag may be derived by the sum of the values of the reference layer corresponding area presence / absence flag of each layer.

ScaledRefLayerOffsetsPresentFlag + = scaled_ref_layer_present_flag [i];
In addition, the inter-layer image prediction restriction flag is included in the SPS extended data when the value of the reference layer corresponding area information group presence / absence flag scaled_ref_layer_offsets_param_present_flag is true (1), and when false, it is not included in the SPS extended data and the value is It may be estimated as false (0). Thereby, the calculation concerning derivation of ScaledRefLayerOffsetsPresentFlag can be omitted.

  The inter-layer image prediction restriction flag may be notified for each reference layer. In addition, the inter-layer image prediction restriction flag is not explicitly included in the parameter set, and the inter-layer image prediction restriction flag is included when reference layer corresponding region information is included in the parameter set (VPS, SPS, PPS, SH, etc.) The value of may be set to 1. That is, when there is reference layer corresponding area information, use of inter-layer image prediction which refers to an image outside the reference layer corresponding area SRLA on the resample reference layer picture rsPic is always prohibited. In this case, the decoding / encoding of the code relating to the inter-layer image prediction restriction flag can be omitted, and the encoding efficiency can be improved.

  Here, the merit of introducing the flag (inter-layer image prediction restriction flag) indicating that the use of the inter-layer image prediction referring to the image outside the reference layer corresponding area SRLA is prohibited will be described using FIG. 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 the outside of 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 resample image rsPicSample of the resample reference layer picture rsPic, the pixels in the portion of the reference layer corresponding area SRLA have pixels corresponding to the reference layer picture rlPic, so the predetermined resample filter (up (Also referred to as sampling filter). On the other hand, there is no pixel corresponding to the reference layer picture rlPic on the pixel of the part of the reference layer corresponding area NSRLA. Therefore, (1) the pixels of the part of the NSRLA outside the reference layer corresponding area are padded (copied) with the border pixels of the reference layer corresponding area SRLA obtained by the resampling closest to each other, or (2) the reference layer corresponding The pixel of the out-of-area NSRLA is replaced with the coordinate (xP ′, yP ′) of the boundary pixel of the reference layer corresponding area closest to that pixel coordinate (xP, yP) and the coordinate (xP ′, yP) of the boundary pixel The position (xRL, yRL) of the reference pixel of the reference layer picture rlPic corresponding to ') is derived, and is generated by applying a predetermined resampling filter centering on the position of the reference pixel. Therefore, inter-layer image prediction that refers only to pixels in the reference layer correspondence area SRLA has high prediction accuracy and leads to improvement in coding efficiency because there is a pixel corresponding to the reference layer picture rlPic. Interlayer image prediction that refers to pixels of the NSRA may lead to a decrease in coding efficiency because the prediction accuracy is low.

  Therefore, by prohibiting the use of inter-layer image prediction that refers to an image outside the reference layer corresponding area SRLA, it is possible to realize an image decoding device and an image coding device with higher coding efficiency. Also, on the image decoding device side, when the inter-layer image prediction restriction flag inter_layer_sample_pred_flag is decoded, if the flag is true, an image outside the reference layer corresponding area SRLA on the resample reference layer picture rsPic in the target sequence. Since it is understood that (reference layer outside the corresponding region NSRLA) is not referred to at the time of inter-layer image prediction, generation of a reference layer outside the region NSRLA is omitted when generating the resampled image rsPicSample of the resample reference layer picture rsPic It is possible to Therefore, it is possible to simplify the resampling process and to reduce the memory required to hold the image of the NSRLA outside the reference layer correspondence area.

(About inter-layer image prediction that refers to an image outside the reference layer correspondence area)
In the following, referring to FIG. 6A, in inter-layer image prediction, the corresponding area RBX on the resample reference layer picture rsPic corresponding to a certain prediction unit PBX on the target picture curPic is more than the reference layer corresponding area SRLA. The conditions 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 area (reference area) on the resample reference layer picture rsPic corresponding to the prediction unit PBX (X = 1... 4) is taken as 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 area is smaller than the left end coordinate (offsetL) of the reference layer corresponding area SRLA (RB1 in FIG. 6A), that is, when the following formula (H-1) is satisfied. is there.

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

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

xP + wPb-1> min (PW-1, PW-OffsetR-1) (H-2)
Here, the reason for the operation of min is that the right end coordinate of the reference layer corresponding area SRLA is larger than the right end coordinate of the resample reference layer picture rsPic (when 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 area is smaller than the upper end coordinate (offsetT) of the reference layer corresponding area SRLA (RB2 in FIG. 6A), that is, when the following expression (H-3) is satisfied is there.

yP <max (0, OffsetT) (H-3)
Here, the reason for the operation of max is to correct to the upper end coordinates (0) of the resample reference layer picture rsPic when the upper end coordinates of the reference layer corresponding area SRLA have a negative value (when offsetT is a negative value). It is.

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

yP + yPb-1> min (PH-1, PH-Offset B-1) (H-4)
Here, the reason for the operation of min is that the right end coordinate of the reference layer corresponding area SRLA is larger than the right end coordinate of the resample reference layer picture rsPic (when 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 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 even one of the above conditions (A1) to (A4) , Refer to an image outside the reference layer corresponding area SRLA.

(For inter-layer image prediction that refers only to images outside the reference layer correspondence area)
The inter-layer image prediction constraint flag described above uses inter-layer image prediction that refers to an image outside the reference layer corresponding area SRLA on the resample reference layer picture rsPic in all prediction units PBX on the target picture curPic Although it has been shown to prohibit, it is not limited to this. For example, the inter-layer image prediction restriction flag prohibits the use of inter-layer image prediction that refers only to the image outside the reference layer corresponding area 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 In the following, referring to FIG. 6B, in the inter-layer image prediction, the corresponding area RBX on the resample reference layer picture rsPic corresponding to a certain prediction unit PBX on the target picture curPic is obtained from the reference layer corresponding area SRLA. The conditions for referring only 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 on the resample reference layer picture rsPic corresponding to the prediction unit PBX (X = 1... 4) is taken as 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 area is smaller than the left end coordinate (offsetL) of the reference layer corresponding area SRLA (RB1 in FIG. 6B), that is, the following expression (H-5) Is the case when

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

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

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

yP> min (PH-1 and PH-Offset B-1) (H-8)
The inter-layer image prediction restriction flag prohibits the use of inter-layer image prediction in which all prediction units PBX on the target picture curPic refer to only the image outside the reference layer corresponding area SRLA on the sample reference layer picture rsPic Since the inter-layer image prediction that refers only to the pixels of the reference layer outside the region with low prediction accuracy is not used even in the case of, similarly, an image decoding device and an image coding device with higher coding efficiency It is possible to realize.

  In the picture parameter set PPS, a set of coding parameters to be referred to by the hierarchical video decoding device 1 for decoding each picture in the target sequence is defined. For example, the reference value of the quantization width used for decoding of a picture and the flag which shows application of weighted prediction are included. A plurality of PPSs may exist in the encoded data. In that case, one of a plurality of PPSs is selected from each picture in the target sequence. The PPS used to decode a particular picture is also referred to as the active PPS. Hereinafter, PPS means active PPS for a target picture unless otherwise noted.

(Picture layer)
In the picture layer, a set of data to which the hierarchical moving image decoding apparatus 1 refers 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 (b) of FIG. (NS is the total number of slices included in the picture PICT).

  In the following, when there is no need to distinguish between slices S0 to SNS-1, suffixes of reference numerals may be omitted and described. Further, the same is true for data included in hierarchically encoded data DATA described below and to which subscripts are attached.

(Slice layer)
In the slice layer, a set of data to which the hierarchical moving image decoding apparatus 1 refers in order to decode a slice S to be processed (also referred to as a target slice) is defined. The slice S includes a slice header SH and slice data SDATA as shown in (c) of FIG.

  The slice header SH includes a coding parameter group to which the hierarchical moving image decoding device 1 refers in order to determine the decoding method of the target slice. The slice type specification information (slice_type) for specifying a slice type is an example of a coding parameter included in the slice header SH.

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

  In the slice header SH, of reference layers that can be referred to in the entire target sequence defined in the VPS, a reference layer (active reference layer) that is actually referred to for inter-layer prediction in decoding / encoding of the target picture Active reference layer specification information inter_pred_enable_flag, num_inter_layer_ref_pics_minus 1 and inter_layer_pred_layer_idc [i] for specifying (refer to SYNSH01 in 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 at the time of decoding of the target picture curPic (also referred to as an inter-layer prediction presence / absence flag), and a value of 1 indicates that inter-layer prediction is used, and the value is 0 Indicates that inter-layer prediction is not used. If not explicitly included in the slice header SH, the value is estimated to be zero. 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 at the time of decoding of the target picture curPic. Specifically, the number of active reference layers NumActiveRefLayerPics is derived, for example, by the following equation (G-9) 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.

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, in the variable RefPicLayerId [i], the layer identifier of the i-th reference layer used for inter-layer prediction of the target picture curPic.

That is, RefPicLayerId [i] = RefLayerId [curLayerId] [inter_layer_pred_layer idc [i]];
Further, the inter-active-layer motion prediction reference layer number NumActivePredRefLayers and the inter-active-layer motion reference layer ActiveMotionPredRefLayerId [i] are derived, for example, by 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)
Also, in the slice header SH, an active reference layer corresponding area indicating which area on the target picture curPic of the target layer actually corresponds to the active reference layer picture separately from the reference layer corresponding area information defined by the SPS. Information (FIG. 7) may be included.

  Syntax active_scaled_ref_layer_offsets_param_present_flag is a flag indicating the presence / absence of the target picture curPic of the target layer curLayerId and the number of active reference layers NumActiveRefLayerPics [curLayerId] pieces of active reference layer corresponding area information, separately from the reference layer corresponding area information specified by SPS (active If the value is true, it indicates that there are several reference layer corresponding area information in the active reference layer. 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 larger than 0, the active reference layer corresponding area information group presence / absence flag is explicitly notified, and when NumDirectRefLayers [curLyaerId] is 0, the active reference layer corresponding area information The group presence / absence flag is estimated to be zero. In the prior art, although the reference layer number NumDirectRefLayers [curLayer] of the target layer is known, the syntax num_scaled_ref_layer_offsets explicitly indicating how many reference layer corresponding area information exists is included. The On the other hand, in the present invention, when the reference layer corresponding area information group presence / absence flag is true, the active reference layer corresponding area information of each active reference layer (NumActiveRefLayers [curLyaerId] pieces of active reference layer corresponding area information) is explicitly notified. It is a structure. By this, it is possible to reduce the code amount related to the active reference layer corresponding area information as compared with the prior art in which the syntax num_scaled_ref_layer_offsets indicating the number of reference layer corresponding area information is notified. Also, 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 to be encoded, the active reference layer corresponding area information group presence / absence flag may be estimated to be zero.

  Note that, instead of SYNSH02 in FIG. 7, a configuration of SYNSH 02A shown in FIG. 34 (a) may be used. That is, when NumActiveRefLayers [curLyaerId] is larger than 1, the active reference layer corresponding area information group presence / absence flag is explicitly notified, and when NumActiveRefLayers [curLyaerId] is 0, the active reference layer corresponding area information group presence / absence flag is 0 If NumActiveRefLayers [curLyaerId] is 1, the active reference layer corresponding area information presence / absence flag is estimated to be 1. This eliminates the need to explicitly notify the active reference layer corresponding area information group presence / absence flag when the number of active reference layers is one, as compared to the example of SYNSH02 in FIG. 7, and the active reference layer corresponding area information group It is possible to reduce the amount of code related to the presence / absence flag. Also, the configuration of SYNSH 02B shown in FIG. 34 (b) may be used. In this case, the active reference layer corresponding area information group presence / absence flag is not included, and NumActiveRefLayers [curLayer] pieces of active reference layer corresponding area information are explicitly notified. Similarly, it is possible to reduce the code amount related to the active reference layer corresponding area information as compared with the prior art in which the syntax num_scaled_ref_layer_offsets indicating the number of reference layer corresponding area information is notified.

  The syntax active_scaled_ref_layer_offset_present_flag [k] is a flag (referred to as an active reference layer corresponding area information presence / absence flag) indicating the presence / absence of active reference layer corresponding area information between the target layer curLayerId and the active reference layer RefPicLayerId [k]. In the case of, 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], active_scaled_ref_layer_bottom_offset [k] are explicitly included as the active reference layer corresponding area information, and false. The values of the above four syntaxes are estimated to be zero respectively. The definition of each syntax is as follows.

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

  active_scaled_ref_layer_right_offset [k] is the lower rightmost pixel of the active reference layer corresponding area SRLA 'on the resampled k-th active reference layer RefPicLayerId [k] used for inter-layer prediction and the lower right luminance pixel of the target picture curPic Offset in the horizontal direction (x direction) between predetermined pixel units.

  active_scaled_ref_layer_bottom_offset [k] is between the lower rightmost pixel of the active reference layer corresponding area SRLA ′ on the resampled k-th reference layer RefPicLayerId [k] used for inter-layer prediction and the lowermost pixel of the target picture curPic It is an offset in the vertical direction (y direction) of a predetermined pixel unit.

  Therefore, when the active reference layer corresponding area information presence / absence flag is 0, it is possible to reduce the code amount related 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]). is there.

  The offsets OffsetL, OffsetT, OffsetR, and OffsetB in FIG. 4 are each syntax of active reference layer corresponding area information between the target layer curLayerId and the active reference layer RefPicLayerId [k] For example, the following equations (G-1A) to (G-4A) are derived using [k], active_scaled_ref_layer_right_offset [k], and active_scaled_ref_layer_bottom_offset [k].

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 a reverse process of formulas (G-1) to (G-4) (I-1) to (I-1) to (I-1) In -4), it is derived similarly by replacing the left side with each corresponding syntax. In addition, the value of each syntax active_scaled_ref_layer_offset_present_flag [k] is a value of 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 set to 1.

  That is, when the active reference layer corresponding area information is notified in the slice header SH, each offset OffsetL, OffsetT, OffsetR, and OffsetB determined by the reference layer corresponding area information notified on the SPS is the active reference layer corresponding area information. It is reset based on. The merit of notifying active reference layer corresponding area information on a slice basis is to notify more accurate reference layer corresponding area information to a sequence in which the corresponding area of the target layer and the reference layer changes on a picture basis. This enables the implementation of more accurate inter-layer motion mapping and inter-layer image mapping. Therefore, since the accuracy of the inter-layer motion mapping and the inter-layer image mapping is improved, the prediction accuracy of the inter-layer motion prediction and the inter-layer image prediction is also improved accordingly, so that it is possible to improve coding efficiency. .

  Further, the data structure of the active reference layer corresponding area information is not limited to the SYNA 05 of FIG. 7, and may be difference information (SYNSH03 of FIG. 8) with respect to the reference layer corresponding area information notified by SPS. Hereinafter, the definition of the syntax of SYNSH03 in FIG. 8 will be described with reference to FIG. Since the active reference layer corresponding area information group presence / absence flag and the active reference layer corresponding area presence / absence flag have been described, they are omitted. In FIG. 9, the corresponding area (reference layer corresponding area) between the image of the target layer and the image of the reference layer will be described. RlPic in the figure is an image (reference layer picture) of a reference layer having an image size of vertical width RLPH and horizontal width RLPW. In the figure, rsPic is an image (resampled reference layer picture) rsPic in which the reference layer picture rlPic is mapped to the image of the target layer having the image size of the vertical width PH and the horizontal width PW. SRLA in the figure is an area (reference layer corresponding area) actually corresponding to the image of the reference layer on the image of the target layer, which is determined by the reference layer corresponding area information notified by the SPS, and the vertical width SRLPH, It has a width of SRLPH. OffsetL on the same figure represents an offset in the horizontal direction (x direction) between the top left pixel of the reference layer corresponding area SRLA and the top left pixel of the resample reference picture rsPic (or the target picture curPic of the target layer). OffsetT in the same figure represents an offset in the vertical direction (y direction) between the top left pixel of the reference layer corresponding area SRLA and the top left pixel of the resample reference picture rsPic (or the target picture curPic of the target layer). OffsetR on the same figure represents an offset in the horizontal direction (x direction) between the lower rightmost pixel of the reference layer corresponding area SRLA and the lower rightmost pixel of the resample reference picture rsPic (or the target picture curPic of the target layer). . OffsetB on the same figure indicates an offset in the vertical direction (y direction) between the lower rightmost pixel of the reference layer corresponding area SRLA and the lower rightmost 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 image of the reference layer on the image of the target layer, which is determined by the active reference layer corresponding area information notified by the slice header SH , Vertical width SRLPH 'and horizontal width SRLPH'. Offset T ′ in the same figure is an offset in the vertical direction (y direction) between the top left pixel of the active reference layer corresponding area SRLA ′ and the top left pixel of the resample reference picture rsPic (or the target picture curPic of the target layer). Show. Offset R ′ in the same figure is the horizontal direction (x direction) between the lower rightmost pixel of the active reference layer corresponding region SRLA ′ and the lower rightmost pixel of the resampled reference picture rsPic (or the target picture curPic of the target layer). Represents an offset. Offset B ′ in the same figure is the vertical direction (y direction) between the lower rightmost pixel of the active reference layer corresponding area SRLA ′ and the lower rightmost pixel of the resampled reference picture rsPic (or the target picture curPic of the target layer). Represents an offset. In the figure, ΔL 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 Represents the difference between and and OffsetB '.

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

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

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

active_diff_scaled_ref_layer_bottom_offset [k] is 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 active reference layer corresponding area SRLA ′ in a predetermined pixel unit.
If the above four syntaxes are not explicitly included in the slice header SH, the value of each syntax is assumed to be zero.

  Therefore, when reference layer corresponding area information is unnecessary in the reference layer i, the active reference layer corresponding area information presence / absence flag is set to 0 so that 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 the case of SYNSH03 in FIG. 8, when the number of active reference layers NumActiveRefLayerPics [curLayerId] is larger than 0, an active reference layer corresponding area information presence / absence flag is explicitly notified, and when the number of active reference layers NumActiveRefLayerPics [curLayerId] is 0, The active reference layer corresponding area information presence / absence flag is estimated to be zero. Instead of SYNSH03 in FIG. 8, a configuration of SYNSH03B shown in FIG. 35A may be used. That is, when NumActiveRefLayers [curLyaerId] is larger than 1, the active reference layer corresponding area information group presence / absence flag is explicitly notified, and when NumActiveRefLayers [curLyaerId] is 0, the active reference layer corresponding area information group presence / absence flag is 0 If NumActiveRefLayers [curLyaerId] is 1, the active reference layer corresponding area information presence / absence flag is estimated to be 1. This eliminates the need to explicitly notify the active reference layer corresponding area information group presence / absence flag when the number of active reference layers is one, as compared with the example of SYNSH03 in FIG. 8, and the active reference layer corresponding area information group It is possible to reduce the amount of code related to the presence / absence flag. Alternatively, the configuration of SYNSH03B shown in FIG. 35 (b) may be used. In this case, the active reference layer corresponding area information group presence / absence flag is not included, and NumActiveRefLayers [curLayer] pieces of active reference layer corresponding area information are explicitly notified. Similarly, it is possible to reduce the code amount related to the active reference layer corresponding area information as compared with the prior art in which the syntax num_scaled_ref_layer_offsets indicating the number of reference layer corresponding area information is notified.

  The offsets Offset L ′, Offset T ′, Offset R ′, and Offset B ′ of the active reference layer corresponding area SRLA ′ in FIG. 9 are the offsets Offset L, Offset T, Offset R, Offset B of the reference layer corresponding area SRLA, and the target layer curLayerId Each syntax of active reference layer corresponding area information between reference layers RefPicLayerId [k] active_scaled_ref_layer_offset_present_flag [k], active_diff_scaled_ref_layer_left_offset [k], active_diff_ref_layer_top_offset [k], active_diff_scaled_ref_layer_active_surface Are derived by the equations (G-1B) to (G-4B) of

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 a reverse process of formulas (G-1B) to (G-4B) (I) It is derived by (I-4B).

active_diff_scaled_ref_layer_left_offset [k] = (Offset L '-Offset L) >>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)
In addition, the value of active_scaled_ref_layer_offset_present_flag [k] is set to 0 when all the values of the syntaxes derived by Equations (I-1B) to (I-4B) are 0, otherwise Is determined by setting to 1.

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

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

  As described above, in comparison with the data structure of SYNA05 in FIG. 7 in which the size of the active reference layer corresponding area is explicitly notified, the active reference layer corresponding area information is notified as difference information with respect to the reference layer corresponding area information notified by SPS. This has the effect of reducing the amount of code required to indicate the size of the active reference layer corresponding area. Hereinafter, the reference layer corresponding area SRLA and the active reference layer area SRLA 'are simply referred to as a reference layer corresponding area SRLA, unless otherwise noted. The active reference layer corresponding area information (reference layer corresponding area in units of pictures) may be notified once at the top slice of each picture. This has the effect of reducing the amount of code required to notify the active reference layer corresponding area information, as compared to the case where notification is made in units of slices making up each picture.

  Also, when the slice type is P slice or B slice, the collocated information collocate_from_I0_flag, collocated_ref_idx, alt_collocated_indication_flag, collocated_ref_layer_idex for specifying temporal motion information described later is included.

The slice header SH may include a PPS identifier (pic_parameter_set_id) indicating a reference to the picture parameter set PPS, which is included in the sequence layer.
Also, in the parameter set such as slice header SH, identification information (dependency_id, temporal_id, quality_id, and view_id) of the spatial scalability, temporal scalability, SNR scalability, and view scalability layers of the target layer is encoded. May be

(Slice data layer)
In the slice data layer, a set of data to which the hierarchical moving image decoding apparatus 1 refers to to decode the slice data SDATA to be processed is defined. The slice data SDATA includes a coding tree unit (CTU: Coding Tree Unit), as shown in (d) of FIG. The coding tree unit CTU is an image area of a fixed size (for example, 64 × 64 pixels) constituting a slice. An image block corresponding to the coding tree unit CTU is referred to as a coding tree block (CTB: Coding Tree Block).

(Encoding tree layer)
In the coding tree layer, as shown in (e) of FIG. 2, a set of data to which the hierarchical moving image decoding apparatus 1 refers in order to decode a coding tree unit to be processed is defined. The coding tree unit is divided by recursive quadtree division. The tree structure obtained by recursive quadtree division is called a coding tree. The coding tree unit CTU includes a split flag (split_flag), and when split_flag is 1, the coding tree unit CTU is further split into four CTUs. If split_flag is 0, the coding tree unit CTU is divided into four coding units (CUs: Coding Units). The coding unit CU is an end node of the coding tree layer and is not further divided in this layer. The coding unit CU is a basic unit of coding / decoding processing.

  If the size of the coding tree unit CTU is 64 × 64 pixels, the size of the coding unit CU is 64 × 64 pixels, 32 × 32 pixels, 16 × 16 pixels, or 8 × 8 pixels. It is possible. The image block corresponding to the coding unit CU is referred to as a coding block (CB: Coding Block).

(Coding unit layer)
As shown in (f) of FIG. 2, in the coding unit layer, a set of data to which the hierarchical moving image decoding apparatus 1 refers in order to decode the coding unit to be processed is defined. Specifically, a coding unit includes a CU header CUH, a prediction tree including one or more prediction units (PUs), and a transform including one or more transform units (TUs) Constructed to contain a tree.

  The CU header CUH defines, for example, prediction type information PType indicating whether the coding unit is a unit using intra prediction or a unit using inter prediction.

  In the prediction tree, a coding unit CU is divided into one or more 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 in the same picture, and inter prediction refers to prediction processing performed between mutually different pictures (for example, between display times, between layer images).

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

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

  Also, in the transform tree, the coding unit CU is divided into one or more transform units TU, and the position and size of each transform unit are defined. The division in the transformation tree includes one in which a region of the same size as the coding unit is allocated as a transformation unit, and one in which a recursive quadtree division is used as in the above-described division of the coding tree block.

  The image block corresponding to the prediction unit PU and the transform unit TU is 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 the prediction parameters associated with the prediction unit. The prediction parameters include intra prediction prediction parameters or inter prediction prediction parameters. Hereinafter, prediction parameters for inter prediction (inter prediction parameters) will be described. The inter prediction parameter includes prediction list use flags predFlagL0 and predFlagL1, reference picture indexes refIdxL0 and refIdxL1, and vectors mvL0 and mvL1. The prediction list use flags predFlagL0 and predFlagL1 are flags indicating whether a reference picture list called an L0 list or an L1 list is used, respectively. When the value is 1, a reference picture list corresponding to each flag is used. . In the present specification, when "a flag indicating whether or not it is XX", when the value is 1 when it is XX, when the value is 0 it is not when it is XX, logical negation, logic In products, etc., 1 is treated as true, 0 as false (the same applies hereinafter). However, in an actual apparatus or method, other values may be used as true values or false values. 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. In addition, the information of a prediction list utilization flag can also be expressed by the below-mentioned inter prediction identifier inter_pred_idc.

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

  In addition, information for specifying inter-layer image prediction may be included as a prediction parameter in order to distinguish between intra prediction and inter prediction. For example, it includes a flag (inter-layer image prediction flag) for specifying whether or not inter-layer image prediction is applied. The inter-layer image prediction flag may also be called texture_rl_fla.

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

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

(An example of reference picture list)
Next, an example of the reference picture list will be described. The reference picture list is a sequence of reference pictures stored in a reference picture memory 306 (FIG. 13) described later. FIG. 10A is a conceptual diagram showing an example of a reference picture list. In the reference picture list 601, five rectangles arranged in a line on the left and right sides respectively indicate reference pictures. The codes P0, P1, Q2, P3 and P4 shown in order from the left end to the right are codes indicating the 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 of P and Q indicate picture order numbers POC (Picture Order Count). The downward arrow just 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.

(Example of reference picture)
Next, an example of a reference picture used when deriving a vector will be described. FIG. 11 is a conceptual diagram showing an example of a reference picture. In FIG. 11, the horizontal axis indicates display time, and the vertical axis indicates the number of layers. The illustrated two vertical rows and three horizontal columns (total of six) rectangles each indicate a picture. Among the six rectangles, the rectangle in the second column from the left of the lower row indicates the 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 at the same display time as the target picture and in a different layer. In inter-layer prediction based on the target picture curPic (P2), a reference picture Q2 is used. The reference picture P1 indicated by the 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 an arrow pointing to the right from the target picture is the same layer as the target picture and is a future picture. The reference picture P1 or P3 is used in motion prediction based on the target picture.

(Inter prediction flag and prediction list use flag)
The relationship between the inter prediction identifier and the prediction list utilization flag predFlagL0 and predFlagL1 can be mutually converted as follows. Therefore, as the inter prediction parameter, a prediction list use flag may be used, or an inter prediction identifier may be used. Also, hereinafter, the determination using the prediction list use flag can 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 forecast and AMVP forecast)
As prediction parameter decoding (encoding) methods, there are 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, prediction parameters of the target PU are derived using prediction parameters of already processed blocks. The merge prediction mode is a mode in which the prediction parameter already derived 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, and the AMVP mode is 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 predicted vector index (mvp_LX_idx) indicating a predicted vector and a difference vector (mvdLX).

  The inter prediction identifier inter_pred_idc is data indicating the type and the 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 L0 list and L1 list, respectively, are used, and both indicate using a single reference picture (uni-prediction). The prediction using the L0 list and the L1 list is called L0 prediction and L1 prediction, respectively. Pred_Bi indicates using two reference pictures (bi-prediction), and indicates using two reference pictures stored in the L0 list and the L1 list. The predicted vector index mvp_LX_idx is an index indicating a predicted vector, and the reference picture index refIdxLX is an index indicating a reference picture stored in the reference picture list. LX is a description method used when L0 prediction and L1 prediction are not distinguished, and parameters for L0 list and parameters for L1 list are distinguished by replacing LX with L0 and L1. 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 not distinguishing refIdxL0 from refIdxL1.

  Merge index merge_idx is an index which shows which prediction parameter is used as a prediction parameter of a decoding object block among prediction parameter candidates (merge candidate) derived | led-out from the block in which the process was completed.

(Motion vector and displacement vector)
There are motion vector and displacement vector in vector mvLX. A motion vector is a displacement between the position of a block in a picture at a display time of a layer and the position of the corresponding block in a picture of the same layer at a different display time (eg, adjacent discrete time) It is a vector shown. The displacement vector is a vector indicating the positional deviation between the position of a block in a picture at a display time of a certain layer and the position of the corresponding block in a picture of a different layer at the same display time. Examples of pictures of different layers include pictures of different resolutions (spatial scalability), pictures of different qualities (SNR scalability), and pictures of different viewpoints (view scalability). In the following description, when the motion vector and the displacement vector are not distinguished, they are simply referred to as the vector mvLX. The prediction vector relating to the vector mvLX and the difference vector are called a prediction vector mvpLX and a difference vector mvdLX, respectively. Whether the vector mvLX and the difference vector mvdLX are a motion vector or a displacement vector is distinguished using a reference picture index refIdxLX attached to the vector.

[Layered 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. 12-22.

(Configuration of hierarchical moving image decoding apparatus)
The schematic configuration of the hierarchical moving image decoding device 1 will be described as follows using FIG. FIG. 12 is a functional block diagram showing a schematic configuration of the hierarchical moving image decoding device 1. The layer moving image decoding device 1 decodes the layer encoded data DATA supplied from the layer moving image encoding device 2 to generate a decoded image POUT # T of the target layer. In the following, the target layer will be described as an enhancement layer. Therefore, the target layer is also an upper layer to the reference layer. Conversely, the reference layer is also a lower layer to the target layer.

    As shown in FIG. 12, the hierarchical moving image decoding device 1 includes an 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 layer encoded data DATA transmitted in units of NAL units in a Network Abstraction Layer (NAL).

  The NAL is a layer provided to abstract communication between a video coding layer (VCL) and a lower system that transmits and stores coded data.

  VCL is a layer that performs moving picture coding processing, and coding is performed in VCL. On the other hand, the lower system referred to 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 in VCL, and a header for appropriately delivering the encoded data to a destination lower system. Also, the encoded data in each layer is NAL unit stored, NAL multiplexed, and transmitted to the hierarchical moving image decoding device 1.

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

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

  The reference layer picture decoding unit 13 decodes the reference layer decoded picture from the reference layer coded data DATA # R. The reference layer decoded picture is a decoded picture of the reference layer used at the time of decoded picture decoding 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. In addition, since the reference layer picture decoding unit 13 has the same function as the target layer picture decoding unit 12, the detailed description will be omitted.

  The 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 using 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 predicted image A generation unit 308, an inverse quantization / inverse DCT unit 311, an addition unit 312, and a resampling unit 314 are included. When the target layer is a base layer, the resampling unit 314 is unnecessary.

  Further, the prediction parameter decoding unit 302 is configured to include 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 the target layer coded 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. Part of 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, layer number vps_max_layers_minus1 ( 3, the layer identifier specification information (SYNVPS 02 in FIG. 3), the reference layer specification information (SYNVPS 04 in FIG. 3), the layer dependency type information (SYNVPS 05 in FIG. 3), the reference layer correspondence area information (FIG. 3) 5, the inter-layer image prediction restriction flag (SYNSPS03 in FIG. 5), the active reference layer specification information (SYNSH01 in FIG. 7), the active reference layer corresponding area information (SYNSH 02 in FIG. 7), the co-located information collocated_from_10_flag , Collocated_ref_idx, alt_collocated_indication_flag, collocated_ref_layer_idex, and so on. Control of which code is to be decoded is performed based on an instruction of the prediction parameter decoding unit 302. The variable-length decoding unit 301 outputs the quantization coefficient to the inverse quantization / inverse DCT unit 311. The quantization coefficient is a coefficient obtained by performing DCT (Discrete Cosine Transform, discrete cosine transformation) on the residual signal in the encoding process and quantizing the coefficient.

  The 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. Then, the decoded prediction parameter is output to the predicted image generation unit 308 and stored in the prediction parameter memory 307. The prediction parameter decoding unit 302 also extracts co-located information collocated_from_I0_flag, collocated_ref_idx, alt_collocated_indication_flag, and collocated_ref_layer_idex for specifying temporal motion information, and stores the extracted information in the prediction parameter memory 307.

  The inter prediction parameter decoding unit 303 refers to the prediction parameter stored in the prediction parameter memory 307 and outputs the inter prediction parameter. 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 the process of predicting a picture block in one picture, for example, the 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 determines, based on the decoded reference layer corresponding area information, the reference layer corresponding area SRLA on the resample reference layer picture rsPic as an inter-layer correspondence parameter related to the reference layer j referenced by the target layer i. The offsets OffsetL, OffsetT, OffsetR, and OffsetB indicating the position of are derived using the equations (G-1) to (G-4) described above, and the horizontal width SRLPW and the vertical width SRLPH of the reference layer corresponding area SRLA are G-5) to (G-6) to derive.

  Subsequently, if there is active reference layer corresponding area information corresponding to the reference layer j referred to by the target layer i, offset Offset L, Offset T, Offset R, Offset B, and reference indicating the position of the reference layer corresponding area SRLA using that information The horizontal width SRLPW and the 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 area information, the offsets OffsetL, OffsetT, OffsetR, and OffsetB are derived by the above formulas (G-1A) to (G-4A), and the reference layer corresponding area SRLA The horizontal width SRLPW and the vertical width SRLPH of the above are derived according to the aforementioned formulas (G-5) to (G-6).

(When using SYNSH03 in FIG. 8)
In addition, when using SYNSH03 in FIG. 8 as the active reference layer correspondence area information, the difference values ΔL, ΔT, ΔR, and ΔB (FIG. 9) are respectively calculated for the offsets OffsetL, OffsetT, OffsetR, and OffsetB that have been derived. Add and derive offsets Offset L ′, Offset T ′, Offset R ′, Offset B ′ (corresponding to the above-mentioned formulas (G-1 B) to (G-4 B)). after that,
The horizontal width SRLPW ′ and the vertical width SRLPH ′ of the active reference layer corresponding area SRLA ′ are derived by the above-described formulas (G-5A) to (G-6A).

  Subsequently, the size ratio ScaleFactor X of the horizontal width of the reference layer corresponding area SRLA to the reference layer picture rlPic and the size ratio ScaleFactor Y of the vertical width are derived using the above formulas (G-7) to (G-8).

  Interlayer correspondence relationship parameters (Offset L, Offset T, Offset R, Offset B, SRLPW, SRL PH, ScaleFactor X, ScaleFactor Y, etc.) derived by the inter-layer information derivation unit 3020 are stored in the prediction parameter memory 307.

  The reference picture memory 306 stores the block of the reference picture (reference picture block) generated by the addition unit 312 described later in a predetermined position for each picture and block to be decoded.

  The prediction parameter memory 307 stores the prediction parameter in 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. Do. The inter prediction parameters to be stored include, for example, a prediction list use flag predFlagLX (inter prediction identifier inter_pred_idc), a reference picture index refIdxLX, and a vector mvLX.

  The prediction image generation unit 308 receives the prediction mode predMode input from the variable length decoding unit 301, and also receives a prediction parameter from the prediction parameter decoding unit 302. Further, the predicted image generation unit 308 reads the reference picture from the reference picture memory 306. The prediction image generation unit 308 generates a prediction picture block P (prediction 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 inter prediction using the prediction picture block P. Generate The predicted picture block P corresponds to PU. The PU corresponds to a part of a picture composed of a plurality of pixels, which is a unit for performing prediction processing as described above, that is, a decoding target block for which the prediction processing is performed once.

  The inter-prediction image generation unit 309 uses the reference picture index refIdxLX for the reference picture list (L0 list or L1 list) for which the prediction list use flag predFlagLX is 1, and based on the block to be decoded, the vector mvLX Is read out from the reference picture memory 306. The inter predicted image generation unit 309 performs prediction on the read reference picture block to generate a predicted picture block P. The inter predicted image generation unit 309 outputs the generated predicted picture block P to the addition unit 312.

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

  The intra prediction image generation unit 310 performs prediction on the read reference picture block in the prediction mode indicated by the intra prediction mode IntraPredMode to generate a prediction 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 addition unit 312.

  The addition unit 312 sets, for each pixel, the signal values of the predicted picture block P input from the inter prediction image generation unit 309 and the intra prediction image generation unit 310 and the decoded residual signal input from the inverse quantization / inverse DCT unit 311. Add to generate a reference picture block. The addition unit 312 stores the generated reference picture block in the reference picture memory 306, and externally outputs a target layer decoded picture POUT # T obtained by integrating the generated reference picture block for each picture.

  The resampling unit 314 uses the reference layer corresponding area information recorded in the prediction parameter memory 307, the inter-layer image prediction restriction flag, the active reference layer corresponding area information, and the reference layer decoded picture decoded by the reference layer picture decoding unit 15. Inter-layer motion mapping unit 316, Inter-layer image mapping, Resample motion information rsPicMotion of resample reference layer picture rsPic and resample image rsPicSample using motion information rlPicMotion of image (referred to as reference layer picture rlPic) and image rlPicSample It generates in the part 315. The generated resample motion information rsPicMotion is stored in the prediction parameter memory 307. Also, the generated resampled image rsPicSample is stored in the reference picture memory 306. The 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 showing the configuration of the inter prediction parameter decoding unit 303 according to this 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 code associated with inter prediction (decoding of syntax element to the variable-length decoding unit 301, the code (syntax element) included in the encoded data, for example, division mode part_mode, A merge flag merge_flag, a merge index merge_idx, an inter prediction identifier inter_pred_idc, a reference picture index refIdxLX, a prediction vector index mvp_LX_idx, and a difference vector mvdLX are extracted.

  The inter prediction parameter decoding control unit 3031 first extracts the merge flag merge_flag. Hereinafter, when expressing that the inter prediction parameter decoding control unit 3031 extracts a syntax element, the decoding of a certain syntax element is instructed to the variable length decoding unit 301, and the corresponding syntax element is read from the encoded data. It 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.

  If the merge flag merge_flag is 0, that is, indicates an AMVP prediction mode, the inter prediction parameter decoding control unit 3031 extracts an AMVP prediction parameter. As AMVP prediction parameters, for example, there are inter prediction identifier inter_pred_idc, reference picture index refIdxLX, vector index mvp_LX_idx, and 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), Further, it is stored 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 derivation unit 3032 (motion information derivation 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 view showing a configuration of a merge prediction parameter derivation unit 3036 (motion information derivation 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 is configured to include a prediction list use flag predFlagLX, a vector mvLX, and a reference picture index refIdxLX.

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

  The space 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 parameters to be read out are prediction parameters relating to each block within a predetermined range from the decoding target block (for example, all or part of the blocks in contact with the lower left end, upper left end and upper right end of the decoding target block) is there. The derived merge candidate is stored in the merge candidate storage unit 303611.

  The temporal merge candidate derivation unit 3036132 predicts the motion information of the reference picture colPic specified by the collocated information from the slice header of the slice including the decoding target block for specifying temporal motion information: collocated_from_10_flag, collocated_ref_idx, alt_collocated_indication_flag, collocated_ref_layer_idx By referring to the parameter memory 307, motion information called a temporal merge candidate is derived. When the value of alt_collocated_indication_flag is 0, motion information of a temporal merge candidate is derived based on the motion information of the reference picture colPic on the same layer specified by collocated_from_10_flag and collocated_ref_idx. On the other hand, when the value of alt_collocated_indication_flag is 1, based on resample motion information rsPicMotion resampled by inter-layer motion mapping 315 motion information rlPicMotion of reference layer picture rlPic specified by collated_ref_layer_idx, motion information of temporal merge candidate To derive.

  The prediction parameter of the block in the reference picture colPic including the lower right coordinate BR of the block to be decoded is read from the prediction parameter memory 307 and is regarded 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 derivation unit 303322 and will be described later. Motion information referred to 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 candidate is stored in the merge candidate storage unit 303611.

  FIG. 16 shows an example of the positional relationship of blocks (blocks including coordinates A0, A1, B0, B1 and B2) which are targets for reading out prediction parameters at the time of spatial merge candidate derivation for block X to be decoded. In addition, regarding the block X to be decoded, an example of the positional relationship of the block (the block including the coordinate BR) in the reference picture colPic to be referred to for prediction parameter (motion information) in temporal merge candidate derivation is shown. A block Y in the drawing is a block in the reference picture colPic at a position corresponding to the decoding target block X. As for the relationship between these block positions, when the space vector candidate derivation unit 303321, which will be described later, derives the vector candidate, the block position for which the prediction parameter is to be read and the time vector candidate derivation unit 303322 derives the vector candidate. The block positions to which the prediction parameters (motion information) are to be referred to are also in the same relation.

  The combined merge candidate derivation unit 3036133 derives a combined merge candidate by combining the vectors of the two different derived merge candidates already derived and stored in the merge candidate storage unit 303611 and the reference picture index as vectors of L0 and L1, respectively. Do. The derived merge candidate is 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 candidate is stored in the merge candidate storage unit 303611.

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

  FIG. 17 is a schematic diagram showing the configuration of the AMVP prediction parameter derivation unit 3032 according to this 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 vector candidate mvpLX based on the reference picture index refIdx, and derives a predetermined number of vector candidates. It is stored in the vector candidate storage unit 30331. The derived vector is determined by the space vector candidate derivation unit 303321, the time vector candidate derivation unit 303322, and the zero vector candidate derivation unit 303323.

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

  The time vector candidate derivation unit 303322 predicts motion information of the reference picture colPic specified by the collocated information from the slice header of the slice including the decoding target block for specifying temporal motion information collocated_from_10_flag, collocated_ref_idx, alt_collocated_indication_flag, and collocated_ref_layer_idx. By referring to the parameter memory 307, motion information called a time vector candidate is derived. A vector relating to the block in the reference picture including the lower right coordinates of the block to be decoded is read out from the prediction parameter memory 307 and is set as a vector candidate. When the value of alt_collocated_indication_flag is 0, motion information of a time vector candidate is derived based on the motion information of the reference picture colPic on the same layer specified by collocated_from_I0_flag and collocated_ref_idx. On the other hand, when the value of alt_collocated_indication_flag is 1, based on resample motion information rsPicMotion in which the motion information rlPicMotion of the reference layer picture rlPic specified by collated_ref_layer_idx is resampled by the inter-layer motion mapping 315, motion information of temporal motion vector candidate Derive

  A method of deriving the reference picture colPic and the lower right coordinate BR will be described below. When inter-layer motion prediction flag alt_collocated_indication_flag is equal to 1, resample reference layer picture rsPic of active reference layer ActiveMotionPredRefLayerId [collocated_ref_layer_idx] specified by co-located reference layer index collocated_ref_layer_idx in same access unit as target picture And the reference picture colPic. If 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 block to be decoded is B slice and colocated information from colocated_from_I0_flag is equal to 0, a reference picture (= RefPicList1 [collocated_ref_idx]) at a position pointed to by temporal index collapsed_ref_idx in reference picture list L1. , And a reference picture colPic to be an object of temporal motion information. On the other hand, even if the slice type is B slice, if the above conditions do not apply, or if the slice type is P slice, the reference picture (= RefPicList0 [collocated_ref_idx]) at the position pointed to by index collocated_ref_idx in reference picture list L0. , And a reference picture colPic to be an object of temporal motion information.

  The lower right coordinates BR derive the lower right coordinates xColBr and yColBr of the block according to the following equation when the coordinates of the block to be decoded are (xPb, yPb) and the size is (nPbW, nPbH) (see FIG. 16).

xColBr = xPb + nPbW
yColBr = yPb + nPbH
Further, the coordinates are generated by the following equation so that the horizontal component and the vertical component of the coordinates become multiples of 16, respectively.

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

  The zero vector candidate derivation unit 303323 generates a zero vector whose horizontal component and vertical component are both zero as vector candidates. The generation of the zero vector is performed 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 target range of a space vector candidate or a target block in a time vector candidate is intra-prediction encoded, it can not be used as a vector candidate because there is no motion vector for the block. As a result, when the number of vector candidates does not reach a predetermined number, the zero vector candidate derivation unit generates a zero vector and outputs the zero vector to the vector candidate storage unit. The vector candidate storage unit 30331 sequentially stores 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 the prediction vector list up to a predetermined number. Here, the predetermined number of vector candidates may be 2, for example, and the vector candidate derivation unit 3033 may derive each vector candidate until the predetermined number is reached, and the subsequent derivation process may be omitted.

  The prediction vector selection unit 3034 selects, as a 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 out 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 block referred to with reference to a block (for example, an adjacent block) in a predetermined range from the block to be decoded. In the adjacent block, a block spatially adjacent to the target block, for example, a left block, an upper block, and a block temporally adjacent to the target block, for example, the same position as the target block, the display time is different. Contains the block obtained from the block. With regard to candidate vectors, a spatial motion vector, a temporal motion vector (or a spatial motion vector (or a spatial motion vector), respectively, to distinguish between the case where the reference block is a block spatially adjacent to the current block and the case where the reference block is temporally adjacent. It may be called temporal motion vector (temporal motion information).

  The adding 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 addition unit 3035 outputs the calculated vector mvLX to the predicted image generation unit 308 (FIG. 13).

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

  The configuration of the inter-layer image mapping unit 315 is shown in FIG. The inter-layer image mapping unit 315 derives the position of the reference pixel in the reference layer picture rlPic corresponding to each pixel of the resample reference layer picture rsPic, and the pixel at the derived position and its periphery And 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 sets the luminance in the range of xP = 0 to PW-1, yP = 0 to PH-1) on the resample reference layer picture rsPic, and xPC = 0 to PWC-1 and yPC = 0. ... generate each pixel value of the color difference in the range of PHC-1). Here, PWC and PHC are respectively the horizontal width and the vertical width in the color difference of the resample reference layer picture rsPic. In addition, when the inter-layer image prediction constraint flag inter_pred_sample_constraint_flag is true, the reference layer corresponding area SRLA (brightness (xP = offsetL ... PW-offsetR-1, yP = offsetT ... PH-offsetB-1), color difference (xPC = 0ffsetL / 2) ... Because only images in the range of PWC-offsetR / 2-1, offsetT / 2 ... PHC-offset / 2-1)) are referenced in inter-layer image prediction, a resample image of only the above range is generated and referenced It may be stored in the picture memory 308. 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.

The reference pixel position derivation unit 3151 uses the inter-layer correspondence relationship parameters (Offset L, Offset T, Offset R, Offset B, SRLPW, SRL PH, ScaleFactor X, ScaleFactor Y) derived by the inter-layer information derivation unit 3020 to obtain a resample 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 in the following procedure, and the resampled image generation unit Output to 3152
(1) The reference pixel position (xRefMP, yRefMP) of 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 1/16 pixel accuracy, then 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 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, in consideration of sample positions of luminance and color difference, in the case of luminance, the expressions (N-1) to (N-2), and in the case of color difference, the expressions (N-1A) to (N-2A), (N- It may be derived by 1B) to (N-2B). Here, phaseX and phaseY are phase differences of sample positions of color difference with respect to 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-1 B);
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 (xRefMP, yRefMP) of 1/2 ^ MP pixel accuracy, reference pixel position value (xRef, yRef) of integer accuracy and phase (xPhase, yPhase) can be expressed as equations (N-3) to Derivate by (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 a predetermined resample filter to the derived reference pixel position (xRef, yRef) and phase (xPhase, yPhase), and generates and generates a resample pixel intSample of luminance and chrominance. The resampled image rsPicSample is stored in the reference picture memory 308.

(For luminance)
First, the range (filter area) of the horizontal position xPosRL (xPosRL = xRef-fs / 2 +1 ... xRef + fs / 2) and the vertical position yPosRL (yPosRL = yRef-1 ... yRef + fs-1) on the reference layer picture rlPic Apply a predetermined resample filter FL (for example, an 8-tap, 1 / 16-pixel-accurate filter shown in FIG. 19) to the pixel rlPicSampleL in), and the pixel tempArray [n] (n = 0 ... fs-1) ) (Formula (N-7)). Here, equation (N-7) represents applying the resampling filter in the horizontal direction. Here, fs represents the number of taps of the filter.

tempArray [n] =
FL FL [x Phase, i] * rlPic Sample L [Clip 3 (0, RLPW-1, xRef-fs / 2 + 1 + i), yPosRL]; (N-7)
Here, with respect to X, Clip 3 (a, b, X) is X ≦ a when X <a and X = b when b <X so that a ≦ X ≦ b. It is a function that limits X. That is, in the above equation, the portion of Clip 3 (0, RLPW-1, xRef-fs / 2 + 1 + i) corresponds to the horizontal reference pixel position (xRef-fs / 2 + 1 + i) to which the resample filter is applied. When the) indicates the coordinates outside the screen, an operation of correcting to the screen edge coordinates is shown. Also, i takes a value of 0... Fs-1. Further, when yPosRL indicates the off-screen coordinates 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 resampling filter FL (for example, an 8-tap, 1/16 pixel accuracy filter shown in FIG. 19) is applied to the derived pixel tempArray [n] (n = 0... Fs-1). The value rsPicSampleL [xP] [yP] of the target pixel (xP, yP) is derived (equations (N-9) to (N-10)). Here, equation (N-9) represents applying the resampling filter 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, horizontal position xPosRL (xPosRL = xRef-fs / 2 + 1 ... xRef + fs / 2) and vertical position yPosRL (yPosRL = yRef-fs / 2 + 1 ... yRef + fs / 2) on the reference layer picture rlPic A predetermined resample filter FC (for example, a 4-tap, 1/16 pixel accuracy filter shown in FIG. 20) is applied to the pixel rlPicSampleC in the range (filter area), and the pixel tempArray [n] (n = 0 ... fs-1) is generated (Expression (N-11)).

tempArray [n] =
FCFC [xPhase, i] * rlPicSampleC [Clip 3 (0, RLPWC-1, xRef-1 + i), yPosRL]; (N-11)
Here, i takes a value of 0... Fs-1. Further, when yPosRL indicates the off-screen coordinates 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 respectively the width and width of the color difference of the reference layer picture rlPic.

  Subsequently, a predetermined resample filter FC (for example, a 4-tap, 1/16 pixel accuracy filter shown in FIG. 20) is applied to the derived pixel tempArray [n] (n = 0... Fs-1). The value rsPicSampleC [xP] [yP] of the target pixel (xP, yP) is derived (equations (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 precision of color difference.

  The inter-layer image mapping unit 315 specifies 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 Identification 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 to be subjected to 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 identification method 2) When the layer ID of the reference picture among the reference pictures included in the reference picture list is different from the layer ID of the image to be decoded, the reference layer for which the reference picture is subjected to inter-layer image mapping It is a picture. Specifically, the layer IDs of the reference pictures of RefPicList0 [] and RefPicList1 [] are scanned, and a reference picture different from the layer ID of the image to be decoded is specified.

  As described above, in the inter-layer image mapping unit 315, the inter-layer correspondence relationship parameters (Offset L, Offset T, Offset R, Offset B, SRLPW, SRL PH, and the like between the target layer (for example, enhancement layer) and the reference layer (for example, base layer)). Based on ScaleFactor X, ScaleFactor Y, etc., determine the position of the reference pixel on the reference layer picture rlPic corresponding to each pixel on the resampled reference layer picture rsPic, and apply a predetermined resample filter to the reference pixel and peripheral pixels By doing this, the target pixel can be generated. Thereby, the effect of improving the accuracy of the resampled image used in the inter-layer image prediction can be obtained. In particular, for a sequence in which the correspondence area between the target layer and the reference layer changes in units of pictures, inter-layer image mapping is performed based on the inter-layer correspondence relationship parameter derived by the reference layer correspondence area information. Inter-layer image mapping is performed based on inter-layer correspondence parameters derived from active reference layer corresponding area information (reference layer corresponding area information in units of pictures), so that the accuracy of the resampled image used in inter-layer image prediction The effect of improving the Along with this, the prediction accuracy of the inter-layer image prediction is also improved, so that the coding efficiency can be improved.

(Operation of inter-layer image mapping in the present invention)
A process of generating resampled pixels regarding coordinates (xP, yP) on the resampled 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 an operation of generation processing of a resampled pixel regarding coordinates (xP, yP) on the resampled 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 sets the reference pixel position (xRefMP, yRefMP) of 1/2 ^ MP pixel accuracy corresponding to each coordinate (xP, yP) to the above-mentioned equations (N-1) to (N). It derives by -2).

  (Step S 803) The reference pixel position deriving unit 3151 uses the derived reference pixel position of 1/2 ^ MP pixel precision to set the reference pixel positions (xRef, yRef) and phase (xPhase, yPhase) of integer pixel precision Derivate by (N-3) to (N-6).

  (Step S804) The resampled image generation unit 3152 sets 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 A predetermined resample filter is applied to the pixel rlPicSampleX (X = L, C) in the range (filter area) of + fs-1), and the pixel tempArray [n] (n = 0 ... fs-1) is obtained. Generate (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, generation processing of resampled pixels regarding 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 an operation of generation processing of a resampled pixel regarding coordinates (xP, yP) on a resampled 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 detects the luminance in the range of xP = 0..PW-1, yP = 0.PH-1 on the resample reference layer picture rsPic, and xPC = 0. When generating each pixel of the color difference in the range of PWC-1, yPC = 0 ... PHC-1, coordinates (xP ', yP') in which the coordinates (xP, yP) are limited within the reference layer corresponding area SRLA Is derived based on Formulas (N-20) to (N-21). That is, as shown in FIG. 31A, when the coordinates (xP, yP) on the resample reference layer picture rsPic are outside the reference layer corresponding area SRLA, the reference layer correspondence closest to the coordinates (xP, yP) This is processing for replacing with the coordinates (xP ′, yP ′) of the boundary pixel 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 converts the reference pixel position (xRefMP, yRefMP) of 1/2 ^ MP pixel accuracy corresponding to the derived coordinates (xP ′, yP ′) into the above equation (XRefMP, yRefMP). N-1) to (N-2).

  (Step S803) The reference pixel position deriving unit 3151 in the prior art calculates reference pixel positions (xRef, yRef) and phase (xPhase, yPhase) of integer pixel accuracy from the derived reference pixel position of 1/2 ^ MP pixel accuracy. It derives from the above-mentioned formulas (N-3) to (N-6).

  (Step S804) The resampled image generation unit 3152 in the prior art detects the horizontal position xPosRL (xPosRL = xRef-fs / 2 +1 ... xRef + fs / 2) on the reference layer picture rlPic, the vertical position yPosRL (yPosRL = yRef- A predetermined resample filter is applied to the pixel rlPicSampleX (X = L, C) in the range of 1 ... yRef + fs-1) to generate a pixel tempArray [n] (n = 0 ... fs-1) (Formula (N-7) or (N-12)).

  (Step S805) The resampled image generation unit 3152 in the related art applies a predetermined resample filter to the derived pixel tempArray [n] (n = 0 ... fs-1) to obtain the target pixel (xP, yP). The value rsPicSampleX [xP] [yP] (X = L, C) is derived (equations (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 the effects of the inter-layer image mapping unit of the present invention will be described. The difference between the prior art and the present invention is that, as shown in FIG. 31A, if the coordinates (xP, yP) on the resample reference layer picture rsPic are outside the reference layer corresponding area SRLA, the coordinates (xP, , yP) is replaced with the coordinates (xP ′, yP ′) of the border pixel of the reference layer corresponding area SRLA closest to the nearest neighbor (step S801 ′ in FIG. 30). As a result, as shown in FIG. 32A, the pixel (xP, yP) of the NSRLA outside the reference layer corresponding area on the resample reference layer picture rsPic in the prior art is the closest on the reference layer corresponding area SRLA. It is identical to the pixel of 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 area SRLA, directly on the reference layer picture rlPic. The reference pixel position (xRef, yRef) is derived. Therefore, it is possible to simplify the derivation process relating to the derivation of the reference pixel position as compared to the prior art.

  Further, in the present invention, the pixel (xP, yP) of the NSRLA outside the reference layer corresponding area on the resample reference layer picture rsPic is the pixel of the border pixel (xP ′, yP ′) on the reference layer corresponding area SRLA. And not necessarily identical. Specifically, in FIG. 32B, outside of the boundary of the reference layer corresponding area SRLA, the area NSRLA ′ (NSRLA ′ on FIG. 32B) having a width ΔFX and a height ΔFY in the horizontal direction is It becomes an area where the pixel value changes smoothly, and the pixel outside the area NSRLA ′ is the same as the boundary pixel of the nearest pixel area NSRLA ′. Here, the sizes of ΔFX and ΔFY are, for example, the number of taps (filter size) fs of the resample filter and the horizontal width of the reference layer corresponding area 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 the reference layer picture rlPic.

ΔFX = (fs * ScaleFactor XA + (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)
ScaleFactor XA is the size ratio of the horizontal width SRLP of the reference layer corresponding area SRLA to the horizontal width RLPW of the reference layer picture rlPic, and ScaleFactor YA is the size ratio of the vertical width SRLPH of SRLA to the vertical width of rsPic. For example, the size of reference layer corresponding area SRLA is 1920x1080 (SRLPW = 1920, SRLPH = 1080), the size of reference layer picture rlPic is 960x540 (RLPW = 960, RLPH = 540), filter size fs = 8, bit precision nosf_bit = 16 In this case, ΔFX = 16 and ΔFY = 16 are derived, respectively, as in the following equation.

ΔFX = (8 * (((1920 << 16) + (960 >> 1)) / 960) + (1 <15)) >> 16 = 16;
ΔFY = (8 * (((1080 << 16) + (540 >> 1)) / 540) + (1 << 15)) >> 16 = 16;
In addition, 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), the filter size fs = 8, bit precision nosf_bit = 16 In this case, ΔFX = 12 and ΔFY = 12, respectively.

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 by, for example, fixing the vertical position yP on the pixel (xP, yP) on the reference layer outside the corresponding area outside the reference layer corresponding area and setting the horizontal position xP in the horizontal direction to xP = 0 ... When changing to offsetT-1, the horizontal position xPosRL (xPosRL = xRef-fs / 2 +1 ... centering on the filter area (reference pixel position (xRef, yRef) on the reference layer picture rsPic) to which the resampling filter is applied Unlike the prior art, the range of xRef + fs / 2), vertical position yPosRL (yPosRL = yRef-1 ... yRef + fs-1), FLTA on FIG. 31 (b), is different from the prior art in coordinates (xP, yP) It is to change accordingly. Note that, 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 end that has a high correlation with that pixel (close spatial distance).

  As described above, the inter-layer image mapping unit in the present invention generates the resample pixel of each coordinate of the non-reference layer corresponding area on the resample reference layer picture rsPic on the reference layer picture rsPic applied by the resample filter. In the filter area FLTA, if there is a pixel at a coordinate outside the screen, a resampled image is generated using a pixel having a high correlation (closer spatial distance) to the pixel. As a result, it is possible to improve the accuracy of the resampled image of the NSRLA outside the reference layer corresponding region as compared with the prior art. In addition, with regard to inter-layer image prediction that refers to pixels of the reference layer corresponding area outside the NSRLA, prediction accuracy can be improved more than in the related art. Therefore, it leads to the improvement of coding efficiency. In particular, in the present invention, a region where the pixel value of the resample image changes smoothly can be generated outside the boundary of the reference layer corresponding region SRLA in the region NSRLA ′ of width ΔFX and height ΔFY in the horizontal direction . Therefore, in the inter-layer image prediction, it is possible to improve the prediction accuracy of the inter-layer image prediction which refers to the region NSRLA 'in the reference layer corresponding region out-of-region NSRLA. Note that the inter-layer image mapping unit in the present invention is independently applicable regardless of the inter-layer image prediction restriction 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 by motion mapping of motion information rlPicMotion of the reference layer picture rlPic.

  The configuration of the inter-layer motion mapping unit 316 is shown in FIG. The inter-layer motion mapping unit 315 determines a 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. And a motion information generation unit 3162 that generates motion information of the target block.

  The reference image block derivation unit 3161 uses the inter-layer correspondence relationship parameters (Offset L, Offset T, Offset R, Offset B, SRLPW, SRL PH, ScaleFactor X, ScaleFactor Y) derived by the inter-layer information derivation unit 3020 to obtain the resample reference layer picture rsPic. The position of the reference image block on the reference layer picture rlPic corresponding to the target block (for example, 16 × 16) in the upper predetermined unit is calculated.

The target block is a block on the resample reference layer picture rsPic to be subjected to 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 in the following procedure.
(1) The center coordinates (xPCtr, yPCtr) of the target block are derived by the 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 central pixel position of the target block. If the size of the target block is 2 ^ M1 × 2 ^ N1 (M1, N1 is a natural number), that is, if the width is 2 ^ M1 and the width is 2 ^ N1, ctrOffsetX = 2 ^ (M1-1), ctrOffsetY = 2 ^ It is preferable to set as (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 center coordinates (xPCtr, yPCtr) of the derived 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 the 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 x 2 ^ N2 of the reference image block. For example, if the size of the reference image block is 16 × 16, then M2 = 4 and N2 = 4. Preferably, the recording unit of the motion information is the same for the reference layer picture rlPic and the resampled reference layer picture rsPic.

  The reference image block derivation unit 3131 outputs the derived position of the reference image block to the motion information generation 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 that, the resample reference layer Resample motion information rsPicMotion of the target block on the picture rsPic (a prediction parameter of the target block referred to as a temporary motion vector of the target block to be decoded) 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 the conditions described later, and the generated motion information (rsPicMotion) is used as the prediction parameter memory 307 Remember to

  The motion information generation unit 3132 determines the prediction parameters as follows according to the coordinates of the reference image block and the prediction mode predMode when generating each of the above-mentioned prediction parameters. 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, either of the following conditional expressions If satisfied, the prediction mode predMode [xP] [yP] is set to the intra prediction mode (MODE_INTRA).

(xRL <0) || (xRL> = RLPW)
(yRL <0) || (yRL> = RLPH)
Here, the symbol || means a logical sum. If none of the above conditions is met, the prediction mode corresponding to the reference image block is generated by substituting it into 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 of the above, when predMode [xP] [yP] becomes the inter prediction mode (MODE_INTER), 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 prediction The prediction parameter of the reference layer picture rlPic corresponding to the list use flag predFlagLX is substituted and set. Specifically, the following equation 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 in the following procedure using the horizontal width SRLPW and the vertical width SRLPH of the reference layer corresponding area SRLA, the horizontal width RLPW and the vertical width RLPH of the reference layer picture rlPic, and the vector mvLXRL of the reference layer picture rlPic.
(1-A) If the horizontal width SRLPW of the reference layer corresponding area SRLA is equal to the horizontal width RLPW of the reference layer picture, the horizontal component vector mvLX [xP] [yP] [0] is set according to the following equation.

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

scaleFactor MVX = Clip 3 (-2 ^ 12, 2 ^ 12-1, ((SRPW << 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 and the vertical width RLPH of the reference layer picture are equal, the vector mvLX [xP] [yP] [1] of the vertical component is set according to the following equation.

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

scaleFactor MVY = Clip 3 (-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 predMode [xP] [yP] after generation is in the intra prediction mode (MODE_INTRA), the picture order number refPOCLX corresponding to the reference picture index refIdxLX and the reference picture index refIdxLX corresponding to the reference picture lists L0 and L1, respectively. The prediction list utilization flag predFlagLX and the vector mvLX are set to be no reference and zero, respectively. Specifically, it is set by the following equation.

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 layer information of the resample reference layer picture rsPic before starting decoding of the target layer. If there is a reference layer picture rlPic input from the reference layer picture decoding unit 13 and the inter-layer motion prediction flag alt_collocated_indication_flag is 1, the inter-layer motion mapping unit 313 predicts a 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 coordinates (xP, yP) on the resample reference layer picture rsPic to be multiples of 16 from 0 to the width and height of the resample reference layer picture rsPic, respectively. . Specifically, the following equation is applied.

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

xPb = 0 ... ((PW + 15) >>4)-1;
yPb = 0 ... ((PH + 15) >>4)-1;
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 Identification Method 1) A reference layer picture specified by co-located information on a slice header is set as a reference layer picture rlPic to be subjected to inter-layer motion mapping. Specifically, the collocated information is included in the slice header and the list L0 flag collated_from_L0_flag specified by the list L0 flag collocated_from_L0_flag and the reference index collated_ref_idx is an image (reference layer picture) including a reference image block from the reference picture list L0 The reference index collated_ref_idx indicates the position (index) of the reference image in the reference picture list. 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 image to be decoded, the reference image colPic is set as a reference layer picture to be subjected to the inter-layer motion mapping.

  (Method 2 for specifying a reference layer picture) If the inter-layer motion prediction flag alt_colloated_indication_flag on the slice header is true (1), the inter-active-layer motion reference layer ActiveMotionPredRefLayerId [collocated_ref_layer_idx] specified by the co-located reference layer ID collocated_ref_layer_idx It is assumed that the reference layer picture rlPic targeted by

  (Reference layer picture identification method 3) When the layer ID of the reference picture among the reference pictures included in the reference picture list is different from the layer ID of the picture to be decoded, the reference layer for which the reference picture is subjected to the inter-layer motion mapping It is a picture. Specifically, the layer IDs of the reference pictures of RefPicList0 [] and RefPicList1 [] are scanned, and a reference picture different from the layer ID of the image to be decoded is specified.

  As described above, in the inter-layer motion mapping unit 316, the inter-layer correspondence relationship parameters (Offset L, Offset T, Offset R, Offset B, SRLPW, SRL PH, and the like between the target layer (eg, enhancement layer) and the reference layer (eg, base layer)). Based on ScaleFactor X, ScaleFactor Y, 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 of the target block is determined based on the motion information of the reference image block. Can be generated. As a result, it is possible to obtain an effect of improving the accuracy of motion information (temporal motion information) used in inter-layer motion prediction. In particular, for a sequence in which the corresponding region of the target layer and the reference layer changes in units of pictures, motion mapping between layers is performed based on the inter-layer correspondence relationship parameter derived by the reference layer corresponding region information. By performing inter-layer motion mapping based on inter-layer correspondence relationship parameters derived from active reference layer corresponding region information (reference layer corresponding region information in units of pictures), motion information (temporal used more in inter-layer motion prediction) The effect of improving the accuracy of motion information) is achieved. Along with this, the prediction accuracy of the inter-layer motion prediction is also improved, so that the coding efficiency can be improved.

<Modification 1 of Prediction Parameter Decoding Unit 302>
In the above-described example, when the prediction type of the target CU is inter prediction, a reference image index indicating the image of the reference layer on the reference image list (resample reference layer picture rsPic) is specified in each PU. Inter-layer image prediction can be used. Whether to use inter-layer image prediction in the target CU is not limited to the above example, and it is possible by explicitly notifying the inter-layer image prediction flag texture_rl_flag in the target CU. FIG. 21 is a diagram showing the configuration of coded data in the case where the inter-layer image prediction flag texture_rl_flag is included in CU units. As shown in FIG. 21, the encoded data in units of CUs is an inter-layer image prediction flag (texture_rl_flag) shown in SYNCU01, CU type information (prediction mode flag (pred_mode_flag)) shown in SYNCU02, and a PU division type (part_mode) shown in SYNCU03. , And PU information and TU information not shown.

  Hereinafter, an operation of decoding encoded data in the case where the inter-layer image prediction flag is included in CU units will be described using FIG.

  (S601) The prediction parameter decoding unit 302 decodes the reference layer specification information and the inter-layer prediction type information for each predetermined parameter set (for example, VPS) unit using the variable length decoding unit 301, and those information Based on the above, the inter-layer image prediction presence / absence flag SamplePredEnableFlag [i] [j] is derived, which indicates whether the target layer i is inter-layer image prediction from the reference layer j. In addition, the variable-length decoding unit 301 is used to decode reference layer corresponding area information for each predetermined parameter set (for example, SPS) unit. Furthermore, the inter-layer image prediction restriction flag is decoded based on the reference layer corresponding area information.

  (S602) The prediction parameter decoding unit 302 decodes the active reference layer corresponding area information for each predetermined parameter set (for example, slice header) using the variable-length decoding unit 301. Further, based on the decoded reference layer corresponding area information and the active reference layer corresponding area information, the prediction parameter decoding unit 302 detects position information of the reference layer corresponding area SRLA on each resample reference layer picture rsPic to which the target picture refers. (Offset L, Offset T, Offset R, Offset B) and size information (SRLPW, SRL PH) are derived. A specific derivation method is omitted since it has been described. Subsequently, the following processing is performed in each CTB.

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

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

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

  In addition, the prediction parameter decoding unit 302 is based on the inter-layer image prediction restriction flag, the coordinates (xP, yP) of the upper leftmost pixel of the target CU, and the CU size log2CbSize (representing the CU size as a logarithmic value with 2 bottom). 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 restriction flag is 1, the corresponding area on the resample reference layer picture rsPic corresponding to the target CU on the target picture curPic is (between the layers referring to the image outside the reference layer corresponding area). Inter-layer image prediction prohibition flag is set to 1 if any of the conditions (A1) to (A4) described in “image prediction” is satisfied (NoInterLayerSamplePredFlag = 1), and otherwise the inter-layer image Set the prediction inhibition 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 the layer identifier curLayerId of the target layer is larger than 0 (which is an enhancement layer), the inter-layer image prediction applicable flag is true, and the inter-layer image prediction prohibition flag is false. In the equation (J-1), when the value is true (Yes in S605), the process transitions to step S606, and the inter-layer image prediction flag texture_rl_flag (SYNCU01 in FIG. 21) is decoded (S606). Otherwise (when the value of the expression (J-1) is false), the process transitions to step S607, the 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 one. If 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 SYNCU 02 in FIG. 21 is decoded. Based on the prediction mode flag, it is determined whether the CU type of the target CU, that is, the intra CU or the inter CU. If the prediction mode flag is 1, it indicates that it is an intra CU, and if it is 0, it indicates that it is an inter CU. In the case of the inter CU, PU split type information (part_mode) shown in SYNCU 03 in FIG. 21 may be further decoded after the prediction mode flag.

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

  (S611) TU information in units of TUs included in the target CU is decoded.

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

  According to the first modification of the prediction parameter decoding unit 302, the inter-layer image prediction applicable flag and the inter-layer enable flag indicate whether the inter-layer image prediction flag (texture_rl_flag) of the target CU (target prediction unit) is explicitly decoded. Control based on the image prediction prohibition flag. In particular, when the inter-layer image prediction restriction flag indicating that inter-layer image prediction including 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 is prohibited is 1, It is ensured between the image decoding apparatus and the image coding apparatus that inter-layer image prediction is not used in which the corresponding region on the resample reference layer picture rsPic corresponding to the target CU straddles the reference layer corresponding region SRLA. Therefore. When the corresponding area on the resample reference layer picture rsPic corresponding to the target CU straddles the reference layer corresponding area SRLA (when any of the above conditions (A1) to (A4) is satisfied), decoding of the inter-layer image prediction flag By omitting (in other words, it is estimated that the inter-layer image prediction flag is 0), it is possible to reduce the amount of processing involved in decoding of the inter-layer image prediction flag. In addition, since the code amount related to the inter-layer image prediction flag can be reduced, the code efficiency can be improved. In addition, since it is compensated that pixels outside the reference layer corresponding area SRLA on the resample reference layer picture rsPic are not referred to in the inter-layer image prediction, the pixels outside the reference layer corresponding area are mapped to the image between layers (resampling The process generated by the process can be omitted. Further, in the reference picture memory, it is possible to reduce the memory for holding the pixels outside the reference layer corresponding area SRLA on the resampled reference layer picture rsPic.

<Modification 2 of Prediction Parameter Decoding Unit 302>
In the above example, when the inter-layer image prediction restriction flag is 1, an inter-layer image that refers to pixels outside the reference layer corresponding area SRLA specified by the reference layer corresponding area information or the active reference layer corresponding area information Although described on the premise to indicate that the use of forecasts is prohibited, it is not limited thereto. When the inter-layer image prediction restriction flag is 1, the use of inter-layer image prediction which refers only to pixels outside the reference layer corresponding area SRLA designated by the reference layer corresponding area information or the active reference layer corresponding area information is prohibited. You may indicate that.

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

  According to the second modification of the prediction parameter decoding unit 302, the inter-layer image prediction applicable flag and the inter-layer image prediction prohibition flag indicate whether or not the inter-layer image prediction flag (texture_rl_flag) of the target CU is explicitly decoded. Control based on In particular, when the inter-layer image prediction restriction 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 secured between the image decoding device and the image coding device. Therefore. When the corresponding area on the resample reference layer picture rsPic corresponding to the target CU refers only to pixels outside the reference layer corresponding area SRLA (when any of the above-described conditions (B1) to (B4) is satisfied), inter-layer By omitting the decoding of the image prediction flag (ie, estimating that the inter-layer image prediction flag is 0), the amount of processing related to the decoding of the inter-layer image prediction flag can be reduced. In addition, since the code amount related to the inter-layer image prediction flag can be reduced, the code efficiency can be improved.

(Layered video decoding device with bit stream restriction)
According to the hierarchical moving image decoding apparatus described above, the inter-layer image prediction restriction flag is decoded, and when the flag is true, the predicted image of the prediction unit is generated by the inter-layer image prediction not satisfying the predetermined condition. However, instead of the inter-layer image prediction restriction flag, a bitstream restriction may be used.

  That is, in a specific profile (for example, a scalable extension profile), the hierarchical moving image decoding device of this 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 above-mentioned CF condition is the same even under the following conditions.

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

  In this case, in the hierarchical moving image decoding device, the prediction image generation unit generates the prediction image of the prediction unit by the inter-layer image prediction not satisfying the predetermined condition when the prediction method of the prediction unit is the inter-layer image prediction. It features.

[Hierarchical Video Coding Device]
Below, the structure of the hierarchy moving image coding apparatus 2 which concerns on this embodiment is demonstrated with reference to FIG.

(Arrangement of Hierarchical Video Coding Device)
The 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 layer moving picture coding device 2. The hierarchical moving image encoding device 2 encodes the input image PIN # T of the target layer with reference to the reference layer coded data DATA # R to generate hierarchically coded data DATA of the target layer. Here, it is assumed that the reference layer coded data DATA # R has already been coded in the hierarchical video coding device corresponding to the reference layer.

  As shown in FIG. 23, the layer moving picture coding apparatus 2 includes a target layer picture coding unit 22, an NAL multiplexing unit 21, and a reference layer picture decoding unit 13.

  The target layer picture coding unit 22 codes the input image PIN # T and outputs the coded data as target layer coded data DATA # T. Further, the target layer picture coding 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 code the input image PIN # T.

  The NAL multiplexing unit 213 generates hierarchical moving image coded data DATA in which NAL multiplexing is performed by storing the input target layer coded data DATA # T and the reference layer coded data DATA # R in the NAL unit. 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 moving image decoding apparatus 1 described above, and the detailed description will be omitted.

(Target layer picture coding unit 22 (image coding apparatus))
The detailed configuration of the target layer picture coding unit 22 will be described using FIG. FIG. 24 is a functional block diagram illustrating the configuration of the target layer picture coding unit 22. The image target layer picture coding unit 22 includes a predicted image generation unit 101, a subtraction unit 102, a DCT / quantization unit 103, a variable length coding 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, coding parameter determination unit 110, prediction parameter coding unit 111, reference layer corresponding area estimation unit 114, resampling unit It comprises 314. The prediction parameter coding unit 111 includes an inter prediction parameter coding unit 112 and an intra prediction parameter coding unit 113. The resampling unit 314 includes an inter-layer image mapping unit 315 and an inter-layer motion mapping unit 316. The resampling unit 314 has a configuration similar to that of the resampling unit 314 in the image decoding apparatus.

  An inter-layer image prediction restriction flag recorded in the prediction parameter memory 108, a reference layer corresponding area information recorded in the prediction parameter memory 108, an active reference layer corresponding area information, and a reference layer picture decoding section Inter-layer motion of resample motion information rsPicMotion of resample reference layer picture rsPic and resample image rsPicSample using motion information rlPicMotion and image rlPicSample of reference layer decoded picture (referred to as reference layer picture rlPic) decoded by 15 The mapping unit 316 generates this in the inter-layer image mapping unit 315. The generated resample motion information rsPicMotion is stored in the prediction parameter memory 108. Also, the generated resampled 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 each input image PIN # T of the target layer input from the outside. Here, the predicted picture generation unit 101 reads the reference picture block from the reference picture memory 109 based on the prediction parameter input from the prediction parameter coding unit 111. The prediction parameter input from the prediction parameter coding unit 111 is, for example, a motion vector or a displacement vector. The prediction image generation unit 101 reads out a reference picture block of a block at a position indicated by a motion vector or a displacement vector predicted from a coding target block as a starting point. The predicted image generation unit 101 generates a predicted picture block P for the read reference picture block using one of a plurality of prediction methods. The prediction image generation unit 101 outputs the generated prediction picture block P to the subtraction unit 102. The prediction image generation unit 101 performs the same operation as the prediction image generation unit 308 described above, and therefore details of generation of the prediction picture block P will be omitted.

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

  The DCT / quantization unit 103 performs DCT on the residual signal input from the subtraction unit 102 to calculate DCT coefficients. The DCT / quantization unit 103 quantizes the calculated DCT coefficient to obtain a quantization coefficient. The DCT / quantization unit 103 outputs the obtained quantization coefficient to the entropy 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 receives the coding parameter from the prediction parameter coding unit 111. The coding parameters to be input include, 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, layer number vps_max_layers_minus1 ( 3, the layer identifier specification information (SYNVPS 02 in FIG. 3), the reference layer specification information (SYNVPS 04 in FIG. 3), the layer dependency type information (SYNVPS 05 in FIG. 3), the reference layer correspondence area information (FIG. 3) 5, the inter-layer image prediction restriction flag (SYNSPS03 in FIG. 5), the active reference layer specification information (SYNSH01 in FIG. 7), the active reference layer corresponding area information (SYNSH 02 in FIG. 7), the co-located information collocated_from_10_flag , Collocated_ref_idx, alt_collocated_indication_flag, collocated_ref_layer_idex, etc.

  The variable-length coding unit 104 performs variable-length coding on the input quantization coefficient and coding parameter to generate target layer coded data DATA # T, and outputs the data 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, for each pixel, the signal value of the predicted picture block P input from the prediction image generation unit 101 and the signal value of the decoded residual signal input from the inverse quantization / inverse DCT unit 105 for reference. Generate a picture block. The addition 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 coding unit 111 in a predetermined position for each picture and block to be coded.

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

  The coding parameter determination unit 110 selects one of a plurality of sets of coding parameters. The coding parameter is a prediction parameter described above or a parameter to be coded that is generated in association with the prediction parameter.

  The coding parameter determination unit 110 calculates, for each of the plurality of sets of coding parameters, a value of the amount of information and a cost value indicating a coding error. The cost value is, for example, the sum of the code amount and a value obtained by multiplying the square error by the coefficient λ. The code amount is the information amount of the target layer coded data DATA # T obtained by subjecting the quantization error and the coding parameter to variable length coding. The squared error is a sum between pixels with respect to the square value of the residual value of the residual signal calculated by the subtraction unit 102. The factor λ is a real number greater than a preset zero. The coding parameter determination unit 110 selects a set of coding parameters that minimize the calculated cost value. As a result, the variable-length coding unit 104 externally outputs the set of selected coding parameters as the target layer coded data DATA # T, and does not output the set of non-selected coding parameters.

  The set of coding parameters to be selected depends on the prediction scheme to be selected. The prediction method to be selected is intra prediction, motion prediction, and merge prediction when the picture to be encoded is a picture of the base layer. Motion prediction is prediction among display times among the above-described inter predictions. Merge prediction is prediction that uses a reference picture block and a prediction parameter that are blocks that have already been coded and that are within a predetermined range from the current block to be coded. When the picture to be encoded is a picture of the upper layer (the 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 coding parameter determination unit 110 outputs the prediction mode predMode corresponding to the selected prediction scheme to the prediction parameter coding unit 111. For example, when motion prediction is selected as the prediction method, the coding parameter determination unit 110 also outputs the 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 at the time of generating the prediction picture block P. The information indicating the motion vector mvLX may include information indicating a reference picture (for example, reference picture index refIdxLX, picture order number POC), and may represent a prediction parameter. When the inter-layer prediction is selected as the prediction method, the coding parameter determination unit 110 also outputs the 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 at the time of generating the predicted picture block P. The information indicating the displacement vector mvLX may include information indicating a reference picture (for example, reference picture index refIdxLX, layer identifier layer_id), and may represent a prediction parameter. When merge prediction is selected as the prediction method, the coding parameter determination unit 110 also outputs the merge index merge_idx.

  Note that the coding parameter determination unit 110 determines that the corresponding region on rsPic on the resample reference picture that the inter-layer image prediction restriction flag is true (1) and the target prediction unit can refer to (from the reference layer corresponding region When any one of the conditions (A1) to (A4) described in “Inter-layer image prediction with reference to the outer image” is satisfied, inter-layer image prediction (refer to different layers) is performed as a prediction method of the target prediction unit Inter prediction, or inter prediction on the same layer. That is, prediction parameters including the reference picture index that satisfies the above conditions are not included in the encoded data. The conditions (B1) to (B4) described in (for inter-layer image prediction in which only the image outside the reference layer corresponding region is referred to) may be used instead of the conditions (A1) to (A4). In inter prediction, inter-layer image prediction can be used by specifying a reference image index indicating an image of a reference layer on the reference image list (resample reference layer picture rsPic).

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

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

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

  The inter prediction parameter coding unit 112 derives inter prediction parameters based on the prediction parameters input from the coding parameter determination unit 110. The inter prediction parameter coding 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 the configuration for deriving the inter prediction parameter. The configuration of the inter prediction parameter coding unit 112 will be described later.

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

  The reference layer corresponding area estimation unit 114 uses the image of the target layer to be input and the image rlSample of the reference layer picture rlPic input from the reference layer picture decoding unit 13 to correspond to the reference layer that indicates the corresponding area of the target layer and the reference layer. Area information (reference layer corresponding area information common to the whole sequence (SYN SPS 02 in FIG. 5), reference layer corresponding area information in picture units (SYN 02 in FIG. 7 or SYNSH 03 in FIG. 8) is calculated, and a prediction parameter coding unit Output to 111. For example, the reference layer corresponding area 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 feature point based matching to obtain corresponding points of the feature points. To calculate the parameters indicating the correspondence between the images (for example, a projective transformation matrix or a rotation matrix and a translation vector). Basically, in scalable coding, the target layer and the reference layer are images having different spatial magnifications and positions, so it is necessary to calculate the magnification (x direction, y direction), and translation. It is a vector (x direction, y direction). A parameter (reference layer corresponding area information (offset L, offset T, offset R, offset B, etc.) indicating the positional relation between the picture of the target layer and the reference layer corresponding area is derived from the parameter indicating the correspondence between the calculated images, and the prediction parameter It is output to the encoding unit 111. Note that the correspondence relationship between the target layer and the reference layer (reference layer correspondence region information) is assumed to be known without including the reference layer correspondence region estimation unit 114, and may be input from the outside. .

  The prediction parameter coding unit 111 uses the reference layer corresponding region information input from the reference layer corresponding region estimation unit 114 to generate each syntax, for example, according to Equations (I-1) to (I-4), (I-1 B) to (I-4B) or the like, and each derived syntax is encoded. The reference layer corresponding area information is output in any unit of slice layer unit, picture layer unit, and sequence layer unit. Further, the prediction parameter coding unit 111 further includes an inter-layer information deriving unit 1160 not shown. The inter-layer information derivation unit 1160 has the same function as the inter-layer information derivation unit 3020 included in the prediction parameter decoding unit 302. Offset Offset L indicating the position of the reference layer corresponding area SRLA on the resample reference layer picture rsPic as an inter-layer correspondence parameter related to the reference layer j referred to by the target layer i based on the encoded reference layer corresponding area information OffsetT, OffsetR, 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 area SRLA are obtained from the above equations (G-5) to (G -6) to derive.

  Subsequently, if there is active reference layer corresponding area information corresponding to the reference layer j referred to by the target layer i, offset Offset L, Offset T, Offset R, Offset B, and reference indicating the position of the reference layer corresponding area SRLA using that information The horizontal width SRLPW and the vertical width SRLPH of the layer corresponding area SRLA are reset.

  Subsequently, the size ratio ScaleFactor X of the horizontal width of the reference layer corresponding area SRLA to the reference layer picture rlPic and the size ratio ScaleFactor Y of the vertical width are derived using the above formulas (G-7) to (G-8).

  Inter-layer correspondence relationship parameters (Offset L, Offset T, Offset R, Offset B, SRLPW, SRL PH, ScaleFactor X, ScaleFactor Y, etc.) derived by the inter-layer information deriving unit 1160 are stored in the prediction parameter memory 108.

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

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

  FIG. 25 is a schematic diagram showing the configuration of the inter prediction parameter coding unit 112 according to the present embodiment. The inter prediction parameter coding unit 112 includes a merge prediction parameter derivation unit 1121, an AMVP prediction parameter derivation unit 1122, a subtraction unit 1123, and an inter prediction parameter coding control unit 1124.

  Merge prediction parameter derivation unit 1121 has a configuration similar to that of merge prediction parameter derivation unit 3036 described above (see FIG. 15).

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

  The AMVP prediction parameter derivation unit 1122 has a configuration similar to that of the above-described AMVP prediction parameter derivation unit 3032 (see FIG. 17).

  When the prediction mode predMode input from the coding parameter determination unit 110 indicates the inter prediction mode, the AMVP prediction parameter derivation unit 1122 receives the vector mvLX from the coding parameter determination unit 110. 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. The reference picture index refIdx and the vector index mvp_LX_idx are output to the inter prediction parameter coding 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 coding parameter determination unit 110 to generate a difference vector mvdLX. The difference vector mvdLX is output to the inter prediction parameter coding 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, for example, the code (syntax element) included in the coded data. 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, difference vector mvdLX are encoded.

  When the prediction mode predMode indicates the merge prediction mode, the inter prediction parameter coding control unit 1124 outputs the merge index merge_idx input from the coding parameter determination unit 110 to the variable length coding unit 104.

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

  As described above, in the inter-layer image mapping unit 315, the inter-layer correspondence relationship parameters (Offset L, Offset T, Offset R, Offset B, SRLPW, SRL PH, and the like between the target layer (for example, enhancement layer) and the reference layer (for example, base layer)). Based on ScaleFactor X, ScaleFactor Y, etc., determine the position of the reference pixel on the reference layer picture rlPic corresponding to each pixel on the resampled reference layer picture rsPic, and apply a predetermined resample filter to the reference pixel and peripheral pixels By doing this, the target pixel can be generated. Thereby, the effect of improving the accuracy of the resampled image used in the inter-layer image prediction can be obtained. In particular, for a sequence in which the correspondence area between the target layer and the reference layer changes in units of pictures, inter-layer image mapping is performed based on the inter-layer correspondence parameter derived by the reference layer correspondence area information, By performing the inter-layer image mapping based on the inter-layer correspondence relationship parameter derived by the active reference layer corresponding region information, the effect of further improving the accuracy of the resampled image used in the inter-layer image prediction can be achieved. Along with this, the prediction accuracy of the inter-layer image prediction is also improved, so that the coding efficiency can be improved.

  As described above, in the inter-layer motion mapping unit 316, the inter-layer correspondence relationship parameters (Offset L, Offset T, Offset R, Offset B, SRLPW, SRL PH, and the like between the target layer (eg, enhancement layer) and the reference layer (eg, base layer)). Based on ScaleFactor X, ScaleFactor Y, 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 of the target block is determined based on the motion information of the reference image block. Can be generated. As a result, it is possible to obtain an effect of improving the accuracy of motion information (temporal motion information) used in inter-layer motion prediction. In particular, for a sequence in which the corresponding region of the target layer and the reference layer changes in units of pictures, inter-layer motion mapping is performed based on the inter-layer correspondence relationship parameter derived by the reference layer corresponding region information. By performing the inter-layer motion mapping based on the inter-layer correspondence relationship parameter derived by the active reference layer correspondence region information, the effect of further improving the accuracy of motion information (temporal motion information) used in inter-layer motion prediction Play. Along with this, the prediction accuracy of the inter-layer motion prediction is also improved, so that the coding efficiency can be improved.

<Modification 1 of Prediction Parameter Encoding Unit 111>
In the above-described example, when the prediction type of the target CU is inter prediction, a reference image index indicating the image of the reference layer on the reference image list (resample reference layer picture rsPic) is specified in each PU. Inter-layer image prediction can be used. Whether to use inter-layer image prediction in the target CU is not limited to the above example, and it is possible by explicitly notifying the inter-layer image prediction flag texture_rl_flag in the target CU. FIG. 21 is a diagram showing the configuration of coded data in the case where the inter-layer image prediction flag texture_rl_flag is included in CU units. As shown in FIG. 21, the encoded data in units of CUs is an inter-layer image prediction flag (texture_rl_flag) shown in SYNCU01, CU type information (prediction mode flag (pred_mode_flag)) shown in SYNCU02, and a PU division type (part_mode) shown in SYNCU03. , And PU information and TU information not shown.

  Hereinafter, an operation of encoding encoded data in the case where the inter-layer image prediction flag is included in CU units will be described using FIG. The first modification of the prediction parameter coding unit 111 corresponds to the reverse process of the prediction parameter decoding unit 302.

(S701) The prediction parameter coding unit 111 determines, for each predetermined parameter set (for example, VPS), based on the reference layer designation information and the inter-layer prediction type information determined by the coding parameter determination unit 110. The inter-layer image prediction presence / absence flag SamplePredEnableFlag [i] [j] indicating the presence / absence of inter-layer image prediction from the reference layer j is derived from the target layer i.
Further, the prediction parameter coding unit 111 instructs the variable-length coding unit 104 to code the reference layer designation information and the code of the inter-layer prediction type information. In addition, the prediction parameter coding unit 111 instructs the variable-length coding unit 104 on the code of the reference layer corresponding area information determined by the coding parameter determination unit 110 for each predetermined parameter set (for example, SPS) unit. And encode. Furthermore, the prediction parameter coding unit 111 instructs the variable-length coding unit 104 to code the inter-layer image prediction constraint flag determined based on the reference layer corresponding area information in the coding parameter determination unit 110. .

  (S702) The prediction parameter coding unit 111 transmits the code of the active reference layer corresponding area information determined by the coding parameter determination unit 110 to the variable length coding unit 104 for each predetermined parameter set (for example, slice header). Directly encode. Furthermore, the prediction parameter coding unit 111 determines, on each resample reference layer picture rsPic that the target picture refers to, based on the reference layer corresponding region information determined by the coding parameter determination unit 110 and the active reference layer corresponding region information. The position information (Offset L, Offset T, Offset R, Offset B) and size information (SRLPW, SRLPH) of the reference layer corresponding area SRLA are derived. A specific derivation method is omitted since it has been described. Subsequently, the following processing is performed in each CTB.

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

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

  (S705) The prediction parameter encoding unit 111 determines whether the target layer curLayerId, the inter-layer image prediction applicable flag InterLayerSamplePredEnableFlag, and the inter-layer image prediction prohibition flag NoInterLayerSamplePredFlag satisfy the above-mentioned equation (J-1). In Formula (J-1), when the value is true (Yes in S705), the process proceeds to step S706, and the prediction parameter coding unit 111 determines the inter-layer image prediction flag texture_rl_flag (determined by the coding parameter determination unit 110). The SYNCU 01) in FIG. 21 is instructed to the variable-length coding unit 110 to be coded (S706). Otherwise (when the value of the expression (J-1) is false), the coding 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 one. If 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) CU type information indicating the CU type of the target CU, for example, the prediction mode flag (pred_mode_flag) shown in SYNCU 02 in FIG. 21 is encoded. In addition, when a prediction mode flag is 0, PU division | segmentation type information (part_mode) shown to SYNCU03 in FIG. 21 may be further encoded after an encoding of a prediction mode flag.

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

  (S711) TU information in units of TUs included in the target CU is encoded.

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

  According to the modification 1 of the prediction parameter coding unit 111, the inter-layer image prediction applicable flag and the inter-layer image prediction prohibition as to whether or not the inter-layer image prediction flag (texture_rl_flag) of the target CU is explicitly encoded Control based on the flag. In particular, when the inter-layer image prediction restriction flag indicating that inter-layer image prediction including 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 is prohibited is 1, It is ensured between the image decoding apparatus and the image coding apparatus that inter-layer image prediction is not used in which the corresponding region on the resample reference layer picture rsPic corresponding to the target CU straddles the reference layer corresponding region SRLA. Therefore. When the corresponding area on the resample reference layer picture rsPic corresponding to the target CU straddles the reference layer corresponding area SRLA (when any of the above-described conditions (A1) to (A4) is satisfied), the code of the inter-layer image prediction flag By omitting this process, it is possible to reduce the amount of processing involved in the encoding of the inter-layer image prediction flag. In addition, since the code amount related to the inter-layer image prediction flag can be reduced, the code efficiency can be improved. In addition, since it is compensated that pixels outside the reference layer corresponding area SRLA on the resample reference layer picture rsPic are not referred to in the inter-layer image prediction, the pixels outside the reference layer corresponding area are mapped to the image between layers (resampling The process generated by the process can be omitted. Further, in the reference picture memory, it is possible to reduce the memory for holding the pixels outside the reference layer corresponding area SRLA on the resampled reference layer picture rsPic.

<Modification 2 of Prediction Parameter Encoding Unit 111>
In the above example, when the inter-layer image prediction restriction flag is 1, an inter-layer image that refers to pixels outside the reference layer corresponding area SRLA specified by the reference layer corresponding area information or the active reference layer corresponding area information Although described on the premise to indicate that the use of forecasts is prohibited, it is not limited thereto. When the inter-layer image prediction restriction flag is 1, the use of inter-layer image prediction which refers only to pixels outside the reference layer corresponding area SRLA designated by the reference layer corresponding area information or the active reference layer corresponding area information is prohibited. You may indicate 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-mentioned conditions (B1) to (B4) instead of the above-mentioned conditions (A1) to (A4).

  According to the second modification of the prediction parameter coding unit 111, the inter-layer image prediction applicable flag and the inter-layer image prediction whether the inter-layer image prediction flag (texture_rl_flag) of the target CU is explicitly encoded or not Control based on the prohibition flag. In particular, when the inter-layer image prediction restriction 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 secured between the image decoding device and the image coding device. Therefore. When the corresponding area on the resample reference layer picture rsPic corresponding to the target CU refers only to pixels outside the reference layer corresponding area SRLA (when any of the above-described conditions (B1) to (B4) is satisfied), inter-layer By omitting the coding of the image prediction flag, it is possible to reduce the amount of processing related to the coding of the inter-layer image prediction flag. In addition, since the code amount related to the inter-layer image prediction flag can be reduced, the code efficiency can be improved.

(Example applied to other hierarchical video coding / decoding systems)
The hierarchical moving image encoding device 2 and the hierarchical moving image decoding device 1 described above can be used by being installed in various devices for transmitting, receiving, recording, and reproducing moving images. The moving image may be a natural moving image captured by a camera or the like, or an artificial moving image (including CG and GUI) generated by a computer or the like.

  Based on FIG. 27, it will be described that the above-described hierarchical moving image encoding device 2 and hierarchical moving image decoding device 1 can be used for transmission and reception of moving images. (A) of FIG. 27 is a block diagram showing a configuration of a transmitter PROD_A on which the hierarchical moving image encoder 2 is mounted.

  As shown in (a) of FIG. 27, the transmission device PROD_A modulates a carrier wave with the coding unit PROD_A1 for obtaining coded data by coding a moving image, and the coding data obtained by the coding unit PROD_A1. Thus, the modulation unit PROD_A2 for obtaining a modulation signal and the transmission unit PROD_A3 for transmitting the modulation signal obtained by the modulation unit PROD_A2 are provided. The above-described hierarchical moving picture coding device 2 is used as the coding unit PROD_A1.

  The transmission device PROD_A is a camera PROD_A4 for capturing a moving image, a recording medium PROD_A5 for recording the moving image, an input terminal PROD_A6 for externally inputting the moving image, and a transmission source of the moving image input to the encoding unit PROD_A1. , And may further include an image processing unit A7 that generates or processes an image. In (a) of FIG. 27, although the configuration in which the transmission device PROD_A includes all of these is illustrated, a part of the configuration may be omitted.

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

  (B) of FIG. 27 is a block diagram showing a configuration of a reception device PROD_B in which the hierarchical moving image decoding device 1 is mounted. As shown in (b) of FIG. 27, the receiver PROD_B demodulates the modulated signal received by the receiver PROD_B1, which receives the modulated signal, and the demodulator PROD_B2, which obtains encoded data by demodulating the modulated signal received by the receiver PROD_B1, and A decoding unit PROD_B3 that obtains a moving image by decoding encoded data obtained by the unit PROD_B2 is provided. The hierarchical moving image decoding device 1 described above is used as the decoding unit PROD_B3.

  The receiving device PROD_B is a display PROD_B4 for displaying a moving image, a recording medium PROD_B5 for recording the moving image, and an output terminal for outputting the moving image to the outside as a supply destination of the moving image output by the decoding unit PROD_B3. It may further comprise PROD_B6. Although (b) of FIG. 27 illustrates the configuration in which the reception device PROD_B includes all of these, a part may be omitted.

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

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

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

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

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

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

  As shown in (a) of FIG. 28, the recording device PROD_C uses the encoding unit PROD_C1, which obtains encoded data by encoding a moving image, and the encoded data obtained by the encoding unit PROD_C1, to the recording medium PROD_M. And a writing unit PROD_C2 for writing. The hierarchical moving image encoding device 2 described above is used as the encoding unit PROD_C1.

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

  In addition, the recording device PROD_C is a camera PROD_C3 for capturing a moving image as a supply source of the moving image input to the encoding unit PROD_C1, an input terminal PROD_C4 for inputting the moving image from the outside, and a reception for receiving the moving image The unit PROD_C5 may further include an image processing unit C6 that generates or processes an image. Although (a) of FIG. 28 exemplifies a configuration in which the recording apparatus PROD_C includes all of these, a part may be omitted.

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

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

  (B) of FIG. 28 is a block showing the configuration of the playback device PROD_D equipped with the above-described hierarchical moving image decoding device 1. As shown in (b) of FIG. 28, the playback device PROD_D decodes the moving image by decoding the encoded data read by the reading unit PROD_D1 that reads the encoded data written to the recording medium PROD_M and the reading unit PROD_D1. And a decryption unit PROD_D2 to be obtained. The hierarchical moving image decoding device 1 described above is used as the decoding unit PROD_D2.

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

  In addition, the playback device PROD_D is a display PROD_D3 that displays a moving image as a supply destination of the moving image output by the decoding unit PROD_D2, an output terminal PROD_D4 that outputs the moving image to the outside, and a transmission unit that transmits the moving image. It may further comprise PROD_D5. Although (b) of FIG. 28 exemplifies a configuration in which the playback device PROD_D includes all of these, a part may be omitted.

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

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

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

  In the latter case, each of the above-described devices includes a CPU that executes instructions of a control program that implements 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. Then, the object of the present invention is a recording medium in which the program code (the executable program, the intermediate code program, the source program) of the control program of each device, which is software that realizes the functions described above, is readable by computer. This can also be achieved by supplying the above respective devices and the computer (or CPU or MPU (Micro Processing Unit)) reading out and executing the program code stored in the recording medium.

  Examples of the recording medium include tapes such as magnetic tape and cassette tape, magnetic disks such as floppy (registered trademark) disk / hard disk, and compact disc read-only memory (CD-ROM) / magneto-optical (MO). Disc including optical disc such as MD (Mini Disc) / DVD (Digital Versatile Disc) / CD-R (CD Recordable), IC card (including memory card) / card such as optical card, mask ROM / EPROM (Erasable) Semiconductor memory such as programmable read-only memory (EEPROM) / EEPROM (registered trademark) (electrically erasable and programmable read-only memory) / flash ROM, or logic circuit such as PLD (programmable logic device) or FPGA (field programmable gate array) And the like can be used.

  Further, each device may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. This communication network is not particularly limited as long as the program code can be transmitted. For example, the Internet, intranet, extranet, LAN (Local Area Network), ISDN (Integrated Services Digital Network), VAN (Value-Added Network), CATV (Community Antenna Television) communication network, Virtual Private Network, A telephone network, a mobile communication network, a satellite communication network, etc. can be used. Also, the transmission medium that constitutes this communication network may be any medium that can transmit the program code, and is not limited to a specific configuration or type. For example, even if wired such as IEEE (Institute of Electrical and Electronic Engineers) 1394, USB, power line carrier, cable TV line, telephone line, ADSL (Asymmetric Digital Subscriber Line) line, infrared rays such as IrDA (Infrared Data Association) or remote control , Bluetooth (registered trademark), IEEE802.11 radio, HDR (High Data Rate), NFC (Near Field Communication), DLNA (Digital Living Network Alliance), mobile phone network, satellite link, and even radio such as terrestrial digital network etc. It 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 can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

  The present invention is suitable for a hierarchical image decoding apparatus that decodes encoded data in which image data is hierarchically encoded, and a hierarchical image encoding apparatus 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 referred to by the hierarchical image decoding device.

1-layer video decoding device (image decoding device)
11 NAL demultiplexing unit 12 target layer picture decoding unit (image decoding apparatus)
13 Reference Layer Picture Decoding Unit (Image Decoding Device)
301 variable length decoding unit 302 prediction parameter decoding unit 303 inter prediction parameter decoding unit 304 intra prediction parameter decoding unit 320 inter-layer information derivation unit 306 reference picture memory 307 prediction parameter memory 308 predicted image generation unit 309 inter predicted image generation unit 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 re-sample 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 Space merge candidate derivation unit 3036132 Temporal merge candidate derivation unit 3036133 Combined 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 Space vector candidate derivation unit 303322 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 coding unit 102 subtraction unit 103 DCT / quantization unit 104 variable length coding unit 105 inverse quantization / inverse DCT unit 106 addition unit 108 prediction parameter coding unit 109 reference picture memory 110 coding Parameter determination unit 111 prediction parameter coding unit 112 inter prediction parameter coding unit 113 intra prediction parameter coding unit 114 reference layer corresponding region estimation unit 1121 merge prediction derivation unit 1122 AMVP prediction parameter derivation unit 1123 subtraction unit 1124 inter prediction parameter coding Control unit 1160 inter-layer information deriving unit

Claims (4)

An image decoding apparatus that decodes hierarchically encoded data, comprising:
A reference layer corresponding area information decoding unit that decodes reference layer corresponding area information indicating a corresponding area of a target layer picture and a reference layer picture by referring to a flag indicating presence or absence of the reference layer corresponding area information;
A resampled image generation unit that generates a resampled image of a reference layer picture using an image of the decoded reference layer picture;
A parameter deriving unit that derives position information of the corresponding area using the reference layer corresponding area information and parameters notified in the parameter set, and further derives a size ratio of each of the reference layer picture to the corresponding area ,
A first reference pixel position deriving unit that derives a first reference pixel position of the reference layer picture in each pixel of the resampled image;
A second reference pixel position deriving unit that derives a second reference pixel position and a phase using the first reference pixel position;
A resampling image generation unit configured to generate each pixel of the resampled image using at least the second reference pixel position, the phase, and the resample filter;
When the coordinates used for the filter processing are outside the screen of the reference layer picture, the resampling image generation unit clips the coordinates to coordinates close to the screen edge of the reference layer picture. apparatus.   The resampling image generation unit clips to 0 when the value of the x coordinate of the coordinates used for the filter processing is smaller than 0, and refers to the reference when the value of the x coordinate is larger than the horizontal width -1 of the reference layer picture. 2. The image decoding apparatus according to claim 1, wherein clipping is performed to the horizontal width -1 of the layer picture. An image decoding method for decoding hierarchical encoded data, comprising:
Decoding reference layer corresponding area information indicating a corresponding area of the target layer picture and the reference layer picture by referring to a flag indicating presence / absence of the reference layer corresponding area information;
Generating a resampled image of the reference layer picture using the image of the decoded reference layer picture;
Deriving position information of the corresponding area using the reference layer corresponding area information and parameters notified in the parameter set ;
Deriving a size ratio of each of the reference layer picture to the corresponding area in the vertical and horizontal directions;
Deriving a first reference pixel position of the reference layer picture at each pixel of the resampled image;
Deriving a second reference pixel position and phase using the first reference pixel position;
Generating each pixel of the resampled image using at least the second reference pixel position, the phase, and the resampling filter.
An image decoding method characterized in that, when coordinates used for filtering are outside the screen of the reference layer picture, the coordinates are clipped to coordinates close to the screen edge of the reference layer picture. An image coding apparatus for coding hierarchical coding data, comprising:
Reference layer corresponding area information encoding unit that encodes reference layer corresponding area information indicating the corresponding area of the reference layer picture in the target layer picture and a flag indicating the presence or absence of the reference layer corresponding area information;
A resampled image generation unit that generates a resampled image of a reference layer picture using an image of a coded reference layer picture;
A parameter deriving unit that derives position information of the corresponding area using the reference layer corresponding area information and parameters notified in the parameter set, and further derives a size ratio of each of the reference layer picture to the corresponding area ,
A first reference pixel position deriving unit that derives a first reference pixel position of the reference layer picture in each pixel of the resampled image;
A second reference pixel position deriving unit that derives a second reference pixel position and a phase using the first reference pixel position;
A resampling image generation unit configured to generate each pixel of the resampled image using at least the second reference pixel position, the phase, and the resample filter;
The image code characterized in that, when the coordinates used for the filtering process are outside the screen of the reference layer picture, the resampling image generation unit clips the coordinates to coordinates close to the screen edge of the reference layer picture. Device.