JP2015073213A - Image decoder, image encoder, encoded data converter, and interest area display system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the code amount of hierarchic encoded data while keeping high the picture quality of a reproduced image of an area of interest.SOLUTION: An image decoder 1 includes a skip slice determination part, a non-skip CTU decoding part, and a skip CTU generation part. A skip slice flag indicating whether an object slice is a skip slice or a non-skip slice is decoded from a slice header. When the skip slice flag indicates that the object slice is the skip slice, a slice header decoding part decodes the number of skip CTUs as the number of CTUs included in the object slice and also generates a decoded image of CTUs as may as the number that the number of skip CTUs indicates by the skip CTU generation part so as to generate a decoded image of the object slice. When the skip slice flag indicates that the object slice is the non-skip slice, on the other hand, the slice header decoding part decodes the CTUs included in the object slice by the non-skip CTU decoding part so as to generate a reproduced image of the object slice.

Description

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

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

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

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

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

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

  Also, a technique for generating encoded data from a plurality of moving images by encoding a plurality of mutually related moving images into layers (hierarchies) is also known, which is called a hierarchical encoding technique . The encoded data generated by the hierarchical encoding technique is also referred to as hierarchical encoded data.

  As a representative hierarchical coding technique, SHVC (Scalable HEVC) based on HEVC is known (Non-Patent Document 2).

  SHVC supports spatial scalability, temporal scalability, and SNR scalability. For example, in the case of spatial scalability, hierarchical encoded data is generated by dividing a plurality of moving images having different resolutions into layers. For example, an image downsampled from the original image to a desired resolution is encoded as a lower layer. Next, the original image is encoded as an upper layer after applying inter-layer prediction in order to remove redundancy between layers.

  As another representative hierarchical encoding technique, MV-HEVC (Multi View HEVC) based on HEVC is known (Non-Patent Document 3).

  MV-HEVC supports view scalability. In view scalability, a moving image corresponding to a plurality of different viewpoints (views) is divided into layers and encoded to generate hierarchical encoded data. For example, a moving image corresponding to a basic viewpoint (base view) is encoded as a lower layer. Next, a moving image corresponding to a different viewpoint is encoded as an upper layer after applying inter-layer prediction.

  Inter-layer prediction in SHVC and MV-HEVC includes inter-layer image prediction and inter-layer motion prediction. In inter-layer image prediction, a predicted image is generated using a decoded image of a lower layer. In inter-layer motion prediction, motion information prediction values are derived using motion information of lower layers. A picture used for prediction in inter-layer prediction is called an inter-layer reference picture. A layer including an inter-layer reference picture is called a reference layer. In the following, reference pictures used for inter prediction and reference pictures used for inter-layer prediction are generically referred to simply as reference pictures.

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

  One application that uses SHVC or MV-HEVC is a video application that takes into account the area of interest. For example, a video playback terminal normally plays back video in the entire area with a relatively low resolution. When a part of the video displayed by the viewer of the video reproduction terminal is designated as the attention area, the attention area is displayed on the reproduction terminal with high resolution.

  The video application considering the attention area as described above is a hierarchical code in which a relatively low resolution video of the entire area is encoded as lower layer encoded data, and a high resolution video of the attention area is encoded as upper layer encoded data. This can be realized using the data. That is, when reproducing the entire region, only the encoded data of the lower layer is decoded and reproduced, and when reproducing the high-resolution video of the region of interest, the encoded data of the upper layer is converted into the encoded data of the lower layer. By additionally transmitting, the application can be realized with a smaller transmission band than when both encoded data for low-resolution video and encoded data for high-resolution video are sent.

"Recommendation H.265 (04/13)", ITU-T (released June 7, 2013) JCT3V-E1004_v6 `` MV-HEVC Draft Text 5 '', Joint Collaborative Team on 3D Video Coding Extension Development of ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC 29 / WG 115th Meeting: Vienna, AT, 27 Jul. -2 Aug. 2013 (Released on August 7, 2013) JCTVC-N1008_v1 `` SHVC Draft 3 '', Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG 16 WP 3 and ISO / IEC JTC 1 / SC 29 / WG 11 14th Meeting: Vienna, AT, 25 July- 2 Aug. 2013 (Released on August 20, 2013)

  However, when transmitting encoded data of the upper layer corresponding to the high-resolution video of the entire region regardless of the region of interest, there is a problem that the code amount is greatly increased compared to transmitting encoded data of only the lower layer. there were.

  In addition, when the encoded data of the upper layer including only the attention area is generated, there is a problem that the processing amount required for generation is large. For example, when different attention areas are specified for each user, it is necessary to generate different upper layer encoded data for each user, but the amount of processing required to generate such upper layer encoded data is large. There is a problem that it is difficult to generate and transmit encoded data of an upper layer corresponding to a region of interest for a large number of users.

  The present invention has been made in view of the above-described problem, and its purpose is to use any one of the encoded data of the upper layer corresponding to the entire region and the encoded data of the upper layer corresponding to the region of interest in the hierarchical encoding method. Is to realize an image encoding device and an image decoding device capable of encoding / decoding. In addition, an object of the present invention is to provide a data structure of encoded data that can generate encoded data of an upper layer corresponding to a region of interest from encoded data of an upper layer corresponding to the entire region without generating a decoded image. And an encoded data conversion apparatus that generates encoded data of an upper layer corresponding to the region of interest from the encoded data of the upper layer.

  In order to solve the above problem, an image decoding apparatus according to the present invention is an image decoding apparatus that decodes higher layer encoded data included in hierarchically encoded data and restores a decoded picture of the upper layer. A slice header decoding unit that decodes a slice header of an upper layer, a non-skip CTU decoding unit that decodes a decoded image of a CTU belonging to a non-skip slice of the upper layer based on slice data, and a skip slice of the upper layer A skip CTU generation unit that generates a decoded image of the CTU to which the slice belongs, wherein the slice header decoding unit decodes or estimates a skip slice flag indicating whether the target slice is a skip slice or a non-skip slice, and the skip slice flag is If the slice indicates a skip slice, the slice The header decoding unit decodes the skip CTU number that is the number of CTUs included in the target slice, and generates the decoded images of the number of CTUs indicated by the skip CTU number by the skip CTU generation unit, thereby decoding the decoded image of the target slice When the skip slice flag indicates that the target slice is a non-skip slice, the decoded image of the target slice is generated by decoding the CTU included in the target slice by the non-skip CTU decoding unit. It is characterized by.

  The image decoding apparatus further includes a parameter set decoding unit that decodes the display area information, and the display area specified by the display area information does not include a tile including a skip slice, and is a tile. Preferably, the included slices include tiles that are all non-skip slices.

  In the image decoding apparatus, the skip CTU number may be decoded from the slice header by applying a variable length code decoding process that maximizes the number of CTUs included in the tile to which the target slice belongs. preferable.

  In the image decoding apparatus, when a picture including the target slice includes one tile, a skip slice flag decoded or estimated by the slice header decoding unit indicates that the target slice is a non-skip slice. Is preferred.

  The image decoding apparatus further includes a parameter set decoding unit that decodes all tile dependency identifiers included in the parameter set, and the all tile dependency identifiers have no motion dependency other than between corresponding tiles, or When indicating that there is no inter-layer dependency other than between tiles, it is preferable that the skip slice flag decoded or estimated by the slice header decoding unit indicates that the target slice is a non-skip slice.

  In the image decoding apparatus, when a picture including the target slice includes two or more tiles, the slice header decoding unit decodes the skip slice flag, and a picture including the target slice includes one tile. The slice header decoding unit preferably estimates a value indicating that the target slice is a non-skip slice as the value of the skip slice flag.

  In the image decoding apparatus, when a picture including the target slice includes two or more tiles, the slice header decoding unit generates a non-skip CTU decoding unit or a skip CTU generation according to the value of the skip slice flag. When the CTU included in the target slice is decoded by selecting any one of the units and the picture including the target slice includes one tile, the slice header decoding unit selects the non-skip CTU decoding unit and selects the target slice It is preferable to decode the CTU included in.

  In the image decoding apparatus, it is preferable that the all-tile dependency identifier includes both information indicating presence / absence of motion dependency other than between corresponding tiles and information indicating presence / absence of inter-layer dependency other than between corresponding tiles. .

  The image decoding apparatus further includes a parameter set decoding unit that decodes all tile dependency identifiers included in the parameter set, the picture including the target slice includes two or more tiles, and the all tile dependency identifier Indicates that there is no motion dependence other than between corresponding tiles, or that there is no inter-layer dependence other than between corresponding tiles, the skip slice flag decoded or estimated by the slice header decoding unit is not the target slice. A skip slice is preferred.

  In order to solve the above problems, an image encoding device according to the present invention is an image encoding device that generates encoded data of an upper layer from an input image, and a slice header code that encodes a slice header of the upper layer. A non-skip CTU encoding unit that encodes a decoded image of a CTU belonging to a non-skip slice of an upper layer based on slice data, and a skip CTU generation that generates a decoded image of a CTU belonging to a skip slice of an upper layer And a parameter set encoding unit that encodes display area information, the slice header encoding unit encodes a skip slice flag indicating whether the target slice is a skip slice or a non-skip slice, and the skip slice flag Indicates that the target slice is a skip slice, the slice The ddda encoding unit encodes the number of skip CTUs, which is the number of CTUs included in the target slice, and generates a decoded image of the number of CTUs indicated by the number of skip CTUs by generating the skip CTU generation unit. And when the skip slice flag indicates that the target slice is a non-skip slice, the non-skip CTU encoding unit generates a CTU included in the target slice to generate a decoded image of the target slice. The display area specified by the display area information does not include tiles including skip slices, and includes tiles that are all non-skip slices. Yes.

  In order to solve the above-described problem, an encoded data conversion apparatus according to the present invention converts an input hierarchical encoded data based on input attention area information, and outputs a hierarchical encoded data after conversion An encoded data conversion apparatus, comprising: a slice correction unit that corrects encoded data of an upper layer based on attention area information, wherein the slice correction unit is configured to perform an upper layer based on an attention area indicated by attention area information. It is characterized in that the encoded data of the upper layer is corrected by changing a slice included in the encoded data, which is not included in the attention area, from a non-skip slice to a skip slice.

  Further, in the encoded data conversion apparatus, the slice correction unit converts a slice included in a tile not included in the attention region from a non-skip slice to a skip slice, which is included in the encoded data of the upper layer. It is preferable to modify the encoded data of the upper layer by changing.

  The encoded data conversion apparatus further includes a parameter set correction unit, wherein the parameter set correction unit indicates display area information included in the parameter set, and a display area indicated by the display area information indicates the attention area information. It is preferable to modify the parameter set by rewriting it so as to match the region of interest.

  In order to solve the above-described problem, an attention area display system according to the present invention is an attention area display system that displays an entire picture and a partial area corresponding to the attention area of a picture using accumulated encoded data. A region-of-interest notification unit that supplies region-of-interest information; a layer-encoded data conversion unit that converts the hierarchical encoded data based on the region-of-interest information to generate post-conversion layer-encoded data; and the post-conversion layer code A hierarchical video decoding unit that decodes the encoded data and outputs a decoded picture of an upper layer and a decoded picture of a lower layer, outputs the decoded picture of the lower layer as an entire display image, and outputs the decoded picture of the upper layer It is characterized by including a display control unit that outputs an attention area display image.

  In the attention area display system, it is preferable that the display control unit does not output the attention area display image when the attention area information indicates that the attention area is not designated.

  In the attention area display system, when the attention area information is changed, the display control unit determines whether the upper layer related to the attention area information after the change from the hierarchical video decoding section from the time when the change is determined. Until the decoded picture is supplied, it is preferable to output the area indicated by the attention area information after the change as a partial area of the decoded picture of the lower layer as the attention area display image.

  When the value of the skip slice flag included in the upper layer slice header indicates that the target slice is a skip slice, the image decoding apparatus according to the present invention uses the skip CTU generation unit without using slice data. A decoded image can be generated. Since the skip CTU generation unit generates the decoded image without using the slice data, the image quality of the decoded image is lower than when the non-skip CTU generation unit decodes the decoded image with reference to the slice data, but less processing is performed. A decoded image can be generated using a small amount of encoded data (slice data). Therefore, the image decoding apparatus according to the present invention decodes hierarchically encoded data that is encoded by using a slice in a region included in the region of interest as a non-skip slice and a slice in a region not included in the region of interest as a skip slice. In this case, it is possible to generate a decoded image with a small amount of processing from encoded data with a small code amount and output it as a decoded picture without impairing the quality of the decoded image in the attention area.

It is a flowchart of the process which determines whether the target slice is a skip slice in the skip slice determination part with which the hierarchical moving image decoding apparatus which concerns on embodiment of this invention is provided. It is a figure for demonstrating the layer structure of the hierarchy coding data which concerns on embodiment of this invention, Comprising: (a) has shown about the hierarchy moving image encoder side, (b) is a hierarchy moving image decoding. The device side is shown. It is a figure for demonstrating the structure of the hierarchy coding data which concerns on embodiment of this invention, Comprising: (a) has shown the sequence layer which prescribes | regulates sequence SEQ, (b) has prescribed | regulated picture PICT. (C) shows the slice layer that defines the slice S, (d) shows the CTU layer that defines the coding tree unit CTU, and (e) shows the code layer 3 illustrates a CU layer that defines a coding unit (CU) included in a coding tree unit CTU. It is a figure explaining the relationship between the picture in the hierarchical coding data which concerns on embodiment of this invention, and a tile slice, (a) has illustrated the division area in the case of dividing a picture by a tile slice, (b ) Exemplifies the relationship between tiles and slices in the structure of encoded data. It is a functional block diagram which shows the schematic structure of the said hierarchy moving image decoding apparatus. It is a functional block diagram which illustrates the structure of the base decoding part contained in the said hierarchy moving image decoding apparatus. This is a part of the syntax table that is referred to when decoding PPS, and is a part related to tile information. It is the figure which illustrated the tile row and tile column at the time of dividing a picture into tiles. This is a part of the syntax table that is referred to when decoding the SPS extension included in the SPS, and is a part related to tile information. It is a table | surface which shows the correspondence of the value of all the layer dependence identifiers, motion dependence, and inter-layer dependence. It is a functional block diagram which illustrates the structure of the slice decoding part contained in the said hierarchy moving image decoding apparatus. This is a part of the syntax table that is referred to when decoding the slice header, and is a part related to slice position information. This is a part of a syntax table that is referred to when decoding a slice header, and is a part related to skip slice information. It is a flowchart of the process which determines whether a target slice is a skip slice. It is a flowchart which shows the procedure of a slice decoding process. This is a part of the syntax table that is referred to at the time of SPS decoding, and is a part related to display area information. It is a figure which illustrates the relationship between the display area which is a partial area | region in a picture, and display area position information. It is a functional block diagram which shows schematic structure of the hierarchy moving image encoder which concerns on one Embodiment of this invention. It is a functional block diagram which illustrates the structure of the slice encoding part contained in the said hierarchy moving image encoder. It is the functional block diagram which showed schematic structure of the hierarchy encoding data converter which concerns on one Embodiment of this invention. It is the block diagram which showed the structure of the attention area display system implement | achieved by the combination of the said hierarchy moving image decoding apparatus, a hierarchy moving image encoding apparatus, and a hierarchy encoding data converter. It is the figure which showed the structure of the transmitter which mounts the said hierarchy moving image encoder, and the receiver which mounts the said hierarchy moving image decoder. (A) shows a transmission device equipped with a hierarchical video encoding device, and (b) shows a reception device equipped with a hierarchical video decoding device. It is the figure which showed the structure of the recording device carrying the said hierarchy moving image encoder, and the reproducing | regenerating apparatus carrying the said hierarchy moving image decoding apparatus. (A) shows a recording device equipped with a hierarchical video encoding device, and (b) shows a playback device equipped with a hierarchical video decoding device.

The hierarchical video decoding device 1, the hierarchical video encoding device 2, and the encoded data conversion device 3 according to an embodiment of the present invention will be described based on FIGS.

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

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

  Also, the encoded data conversion device 3 according to the present embodiment converts the encoded data that has been hierarchically encoded by the hierarchical moving image encoding device 2, and converts the encoded data related to a predetermined attention region (the attention region encoded data). ) Is generated. The attention area encoded data can be decoded by the hierarchical moving picture decoding apparatus 1 according to the present embodiment.

  Prior to detailed description of the hierarchical video encoding device 2, the hierarchical video decoding device 1, and the hierarchical encoded data conversion device 3 according to the present embodiment, first, (1) the hierarchical video encoding device 2 or the hierarchical code. A layer structure of hierarchically encoded data generated by the encoded data conversion device 3 and decoded by the hierarchical video decoding device 1 will be described, and then (2) a specific example of a 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 with reference to FIG. FIG. 2 is a diagram schematically illustrating a case where a moving image is hierarchically encoded / decoded by three layers of a lower layer L3, a middle layer L2, and an upper layer L1. That is, in the example shown in FIGS. 2A and 2B, of the three layers, the upper layer L1 is the highest layer and the lower layer L3 is the lowest layer.

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

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

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

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

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

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

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

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

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

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

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

  Also, a part or all of the encoded data related to the decoded image of a specific hierarchy is encoded independently of the other hierarchy, and it is not necessary to refer to information of the other hierarchy when decoding the specific hierarchy. Hierarchically encoded data may be configured as described above. For example, in the example described above with reference to FIGS. 2A and 2B, it has been described that “C” and “B” are referred to for decoding the decoded image POUT # B, but the present invention is not limited thereto. It is also possible to configure the hierarchically encoded data so that the decoded image POUT # B can be decoded using only “B”. For example, it is possible to configure a hierarchical video decoding apparatus that receives the hierarchically encoded data composed only of “B” and the decoded image POUT # C for decoding the decoded image POUT # B.

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

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

  Upper layer: A layer positioned higher than a certain layer is referred to as an upper layer. For example, in FIG. 2, the upper layers of the lower layer L3 are the middle layer L2 and the upper layer L1. The decoded image of the upper layer means a decoded image with higher quality (for example, high resolution, high frame rate, high image quality, etc.).

  Lower layer: A layer located lower than a certain layer is referred to as a lower layer. For example, in FIG. 2, the lower layers of the upper layer L1 are the middle layer L2 and the lower layer L3. Further, the decoded image of the lower layer refers to a decoded image with lower quality.

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

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

  In the example shown in FIGS. 2A and 2B, the reference layers of the upper hierarchy L1 are the middle hierarchy L2 and the lower hierarchy L3. However, the present invention is not limited to this, and the hierarchically encoded data can be configured so that it is not necessary to refer to all of the lower layers in decoding of the specific layer. For example, the hierarchical encoded data can be configured such that the reference layer of the upper hierarchy L1 is either the middle hierarchy L2 or the lower hierarchy L3.

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

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

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

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

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

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

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

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

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

(Basic layer)
FIG. 3 is a diagram illustrating a data structure of encoded data (hierarchically encoded data DATA # C in the example of FIG. 2) that can be employed in the base layer. Hierarchically encoded data DATA # C illustratively includes a sequence and a plurality of pictures constituting the sequence.

  FIG. 3 shows a hierarchical structure of data in the hierarchically encoded data DATA # C. 3A to 3E respectively show a sequence layer that defines the sequence SEQ, a picture layer that defines the picture PICT, a slice layer that defines the slice S, and a coding tree unit (CTU). It is a figure which shows the CU layer which prescribes | regulates the coding unit (Coding Unit; CU) contained in the CTU layer and coding tree unit CTU to prescribe | regulate.

(Sequence layer)
In the sequence layer, a set of data referred to by the hierarchical video decoding device 1 for decoding a sequence SEQ to be processed (hereinafter also referred to as a target sequence) is defined. As shown in FIG. 3A, 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), and pictures PICT _{1 to} PICT. _{It includes NP} (NP is the total number of pictures included in the sequence SEQ) and supplemental enhancement information (SEI).

  In the video parameter set VPS, the number of layers included in the encoded data and the dependency relationship between the layers are defined.

  In the sequence parameter set SPS, a set of encoding parameters referred to by the hierarchical video decoding device 1 for decoding the target sequence is defined. A plurality of SPSs may exist in the encoded data. In that case, an SPS used for decoding is selected from a plurality of candidates for each target sequence. An SPS used for decoding a specific sequence is also called an active SPS. In the following, unless otherwise specified, it means an active SPS for the target sequence.

  In the picture parameter set PPS, a set of encoding parameters referred to by the hierarchical video decoding device 1 for decoding each picture in the target sequence is defined. A plurality of PPS may exist in the encoded data. In that case, one of a plurality of PPSs is selected from each picture in the target sequence. A PPS used for decoding a specific picture is also called an active PPS. In the following, unless otherwise specified, PPS means active PPS for the current picture.

  The active SPS and the active PPS may be set to different SPSs and PPSs for each layer.

(Picture layer)
In the picture layer, a set of data that is referred to by the hierarchical video decoding device 1 in order to decode a picture PICT to be processed (hereinafter also referred to as a target picture) is defined. As shown in FIG. 3B, the picture PICT includes slice headers SH _{1 to} SH _NS and slices S _{1 to} S _NS (NS is the total number of slices included in the picture PICT).

Hereinafter, when it is not necessary to distinguish each of the slice headers SH _{1 to} SH _NS and the slices S _{1 to} S _NS , the reference numerals may be omitted. The same applies to other data with subscripts included in hierarchically encoded data DATA # C described below.

The slice header SH _k includes a coding parameter group referred to by the hierarchical video decoding device 1 in order to determine a decoding method for the corresponding slice S _k . For example, an SPS identifier (seq_parameter_set_id) that specifies SPS and a PPS identifier (pic_parameter_set_id) that specifies PPS are included. The slice type designation information (slice_type) for designating the slice type is an example of an encoding parameter included in the slice header SH.

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

(Slice layer)
In the slice layer, a set of data that is referred to by the hierarchical video decoding device 1 in order to decode a slice S (also referred to as a target slice) to be processed is defined. As shown in FIG. 3C, the slice S includes coding tree units CTU _{1 to} CTU _NC (NC is the total number of CTUs included in the slice S).

(CTU layer)
In the CTU layer, a set of data referred to by the hierarchical video decoding device 1 for decoding a coding tree unit CTU to be processed (hereinafter also referred to as a target CTU) is defined. Note that the coding tree unit may be referred to as a coding tree block (CTB) or a maximum coding unit (LCU).

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

  The coding tree unit CTU is divided into units for specifying a block size for each process of intra prediction or inter prediction and transformation.

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

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

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

  The root of the coding tree is associated with the coding tree unit CTU. In other words, the coding tree unit CTU is associated with the highest node of the tree structure of the quadtree partition that recursively includes a plurality of coding nodes.

  Note that the size of each coding node is half of the size of the coding node that is the parent node of the coding node (that is, the node one layer higher than the coding node).

  Also, the size of the coding tree unit CTU and the size that each coding unit can take are the size designation information of the minimum coding node and the maximum coding node and the minimum coding node included in the sequence parameter set SPS. Depends on hierarchy depth difference. For example, when the size of the minimum coding node is 8 × 8 pixels and the difference in the layer depth between the maximum coding node and the minimum coding node is 3, the size of the coding tree unit CTU is 64 × 64 pixels. Thus, the size of the encoding node can take any of four sizes, that is, 64 × 64 pixels, 32 × 32 pixels, 16 × 16 pixels, and 8 × 8 pixels.

(CTU header)
The CTU header CTUH includes an encoding parameter referred to by the hierarchical video decoding device 1 in order to determine a decoding method of the target CTU. Specifically, as shown in FIG. 3 (d), CTU division information SP_CTU for designating a division pattern of the target CTU into each CU, and a quantization parameter difference Δqp (for designating the quantization step size) qp_delta).

  The CTU division information SP_CTU is information representing a coding tree for dividing the CTU, and specifically, information specifying the shape and size of each CU included in the target CTU and the position in the target CTU. It is.

  Note that the CTU partition information SP_CTU may not explicitly include the shape or size of the CU. For example, the CTU division information SP_CTU may be a set of flags indicating whether or not the entire target CTU or a partial region of the CTU is to be divided into four. In that case, the shape and size of each CU can be specified by using the shape and size of the CTU together.

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

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

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

  In the prediction tree, the encoding node is divided into one or a plurality of prediction blocks, and the position and size of each prediction block are defined. In other words, the prediction block is one or a plurality of non-overlapping areas constituting the encoding node. The prediction tree includes one or a plurality of prediction blocks obtained by the above division.

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

  Broadly speaking, there are two types of partitioning in the prediction tree (hereinafter abbreviated as PU partitioning): intra prediction and inter prediction.

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

  In the case of inter prediction, 2N × 2N (the same size as the encoding node), 2N × N, 2N × nU, 2N × nD, N × 2N, nL × 2N, nR × 2N, and the like are used as division methods. is there.

  In the transform tree, the encoding node is divided into one or a plurality of transform blocks, and the position and size of each transform block are defined. In other words, the transform block is one or a plurality of non-overlapping areas constituting the encoding node. The conversion tree includes one or a plurality of conversion blocks obtained by the above division.

  There are two types of division in the transformation tree: one in which an area having the same size as that of a coding node is assigned as a transformation block, and the other in division by recursive quadtree division as in the above-described division of a tree block.

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

(Data structure of CU information)
Next, specific contents of data included in the CU information CU will be described with reference to FIG. As shown in FIG. 3E, the CU information CU specifically includes a skip flag SKIP, prediction tree information (hereinafter abbreviated as PT information) PTI, and conversion tree information (hereinafter abbreviated as TT information). Include TTI).

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

[PT information]
The PT information PTI is information related to a prediction tree (hereinafter abbreviated as PT) included in the CU. In other words, the PT information PTI is a set of information related to each of one or a plurality of PUs included in the PT, and is referred to when a predicted image is generated by the hierarchical video decoding device 1. As shown in FIG. 3E, the PT information PTI includes prediction type information PType and prediction information PInfo.

  The prediction type information PType is information that specifies a predicted image generation method for the target PU. In the base layer, it is information that specifies whether intra prediction or inter prediction is used.

  The prediction information PInfo is prediction information used in the prediction method specified by the prediction type information PType. In the base layer, intra prediction information PP_Intra is included in the case of intra prediction. In the case of inter prediction, inter prediction information PP_Inter is included.

  The inter prediction information PP_Inter includes prediction information that is referred to when the hierarchical video decoding device 1 generates an inter prediction image by inter prediction. More specifically, the inter prediction information PP_Inter includes inter PU division information that specifies a division pattern of the target CU into each inter PU, and inter prediction parameters (motion compensation parameters) for each inter PU. Examples of inter prediction parameters include a merge flag (merge_flag), a merge index (merge_idx), an estimated motion vector index (mvp_idx), a reference picture index (ref_idx), an inter prediction flag (inter_pred_flag), and a motion vector residual (mvd) including.

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

  Here, the intra prediction parameter is a parameter for restoring intra prediction (prediction mode) for each intra PU. The parameters for restoring the prediction mode include mpm_flag which is a flag related to MPM (Most Probable Mode, the same applies hereinafter), mpm_idx which is an index for selecting the MPM, and an index for specifying a prediction mode other than MPM. Rem_idx is included. Here, MPM is an estimated prediction mode that is highly likely to be selected in the target partition. For example, the MPM may include an estimated prediction mode estimated based on prediction modes assigned to partitions around the target partition, and a DC mode or Planar mode that generally has a high probability of occurrence.

  In the following description, when simply described as “prediction mode”, it means the luminance prediction mode unless otherwise specified. The color difference prediction mode is described as “color difference prediction mode” and is distinguished from the luminance prediction mode. The parameter for restoring the prediction mode includes chroma_mode that is a parameter for designating the color difference prediction mode.

[TT information]
The TT information TTI is information regarding a conversion tree (hereinafter abbreviated as TT) included in the CU. In other words, the TT information TTI is a set of information regarding each of one or a plurality of transform blocks included in the TT, and is referred to when the hierarchical video decoding device 1 decodes residual data.

As shown in FIG. 3 (e), the TT information TTI includes TT division information SP_TT that specifies a division pattern of the target CU into each transform block, and quantized prediction residuals QD _{1 to} QD _NT (NT is the target The total number of blocks included in the CU).

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

  For example, when the CU size is 64 × 64, each transform block obtained by the division can take a size from 32 × 32 pixels to 4 × 4 pixels.

  Each quantization prediction residual QD is encoded data generated by the hierarchical video encoding device 2 performing the following processes 1 to 3 on a target block that is a conversion block to be processed.

Process 1: The prediction residual obtained by subtracting the prediction image from the encoding target image is subjected to frequency conversion (for example, DCT conversion (Discrete Cosine Transform) and DST conversion (Discrete Sine Transform));
Process 2: Quantize the transform coefficient obtained in Process 1;
Process 3: Variable length coding is performed on the transform coefficient quantized in Process 2;
Note that the quantization parameter qp described above represents the size of the quantization step QP used when the hierarchical moving image encoding apparatus 2 quantizes the transform coefficient (QP = 2 ^{qp / 6} ).

(PU partition information)
The PU partition type specified by the PU partition information includes the following eight patterns in total, assuming that the size of the target CU is 2N × 2N pixels. That is, 4 symmetric splittings of 2N × 2N pixels, 2N × N pixels, N × 2N pixels, and N × N pixels, and 2N × nU pixels, 2N × nD pixels, nL × 2N pixels, And four asymmetric splittings of nR × 2N pixels. N = 2 ^m (m is an arbitrary integer of 1 or more). Hereinafter, a prediction unit obtained by dividing the target CU is referred to as a prediction block or a partition.

(Enhancement layer)
For encoded data included in the layer representation of the enhancement layer (hereinafter, enhancement layer encoded data), for example, a data structure substantially similar to the data structure shown in FIG. 3 can be adopted. However, in the enhancement layer encoded data, additional information can be added or parameters can be omitted as follows.

  In the slice layer, spatial scalability, temporal scalability, SNR scalability, and view scalability hierarchy identification information (dependency_id, temporal_id, quality_id, and view_id, respectively) may be encoded.

  Further, the prediction type information PType included in the CU information CU is information that specifies whether the prediction image generation method for the target CU is intra prediction, inter prediction, or inter-layer image prediction. The prediction type information PType includes a flag (inter-layer image prediction flag) that specifies whether or not to apply the inter-layer image prediction mode. Note that the inter-layer image prediction flag may be referred to as texture_rl_flag, inter_layer_pred_flag, or base_mode_flag.

  In the enhancement layer, it may be specified whether the CU type of the target CU is an intra CU, an inter-layer CU, an inter CU, or a skip CU.

  An intra CU can be defined similarly to an intra CU in the base layer. In the intra CU, the inter-layer image prediction flag is set to “0”, and the prediction mode flag is set to “0”.

  An inter-layer CU can be defined as a CU that uses a decoded image of a picture of a reference layer to generate a predicted image. In the inter-layer CU, the inter-layer image prediction flag is set to “1” and the prediction mode flag is set to “0”.

  The skip CU can be defined in the same manner as in the HEVC scheme described above. For example, in the skip CU, “1” is set in the skip flag.

  The inter CU may be defined as a CU that applies non-skip and motion compensation (MC). In the inter CU, for example, “0” is set in the skip flag and “1” is set in the prediction mode flag.

  Further, as described above, the encoded data of the enhancement layer may be generated by an encoding method different from the encoding method of the lower layer. That is, the encoding / decoding process of the enhancement layer does not depend on the type of the lower layer codec.

  The lower layer may be encoded by, for example, MPEG-2 or H.264 / AVC format.

  In the enhancement layer encoded data, the VPS may be extended to include a parameter representing a reference structure between layers.

  Also, in the enhancement layer encoded data, SPS, PPS, and slice header are extended, and information related to a decoded image of a reference layer used for inter-layer image prediction (for example, an inter-layer reference picture set, an inter-layer reference picture list described later) , Syntax for deriving base control information or the like directly or indirectly).

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

[Relationship between pictures, tiles, and slices]
Next, with respect to pictures, tiles, and slices, which are important concepts according to the present invention, the mutual relationship and the relationship with encoded data will be described with reference to FIG. FIG. 4 is a diagram for explaining the relationship between pictures and tile slices in hierarchically encoded data. A tile is associated with a rectangular partial area in a picture and encoded data relating to the partial area. A slice is associated with a partial area in a picture and encoded data related to the partial area, that is, a slice header and slice data related to the partial area.

  FIG. 4A illustrates an example of divided areas when a picture is divided by tile slices. In FIG. 4A, the picture is divided into six rectangular tiles (T00, T01, T02, T10, T11, T12). Each of the tile T00, the tile T02, the tile T10, and the tile T12 includes one slice (in order, a slice S00, a slice S02, a slice S10, and a slice S12). On the other hand, the tile T01 includes two slices (slice S01a and slice S01b), and the tile T11 includes two slices (slice S11a and slice S11b).

  FIG. 4B illustrates the relationship between tiles and slices in the configuration of encoded data. First, encoded data includes a plurality of VCL (Video Coding Layer) NAL units and non-VCL (non-VCL) NAL units. The encoded data of the video encoding layer corresponding to one picture is composed of a plurality of VCL NALs. When a picture is divided into tiles, the encoded data corresponding to the picture includes encoded data corresponding to the tiles in the tile raster order. That is, as shown in FIG. 4A, when a picture is divided into tiles, encoded data corresponding to tiles is included in the order of tiles T00, T01, T02, T10, T11, and T12. When a tile is divided into a plurality of slices, the encoded data corresponding to the slice is changed to the encoded data corresponding to the tile in the order of the CTU at the head of the slice starting from the slice positioned first in the CTU raster scan order within the tile. included. For example, as shown in FIG. 4A, when the tile T01 includes slices S01a and S01b, the encoded data corresponding to the slices are included in the encoded data corresponding to the tile T01 in order of the slices S01a and S01b. .

  As can be seen from the above description, encoded data corresponding to one or more slices is associated with encoded data corresponding to a specific tile in a picture. Therefore, if a decoded image of a slice associated with a tile can be generated, a decoded image of a partial region in a picture corresponding to the tile can be generated.

  The following description will be made on the premise of the relationship between the picture, tile, slice, and encoded data as described above unless otherwise specified.

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

(Configuration of Hierarchical Video Decoding Device)
The schematic configuration of the hierarchical video decoding device 1 will be described with reference to FIG. FIG. 5 is a functional block diagram showing a schematic configuration of the hierarchical video decoding device 1. The hierarchical video decoding device 1 receives hierarchical encoded data DATA (hierarchical encoded data DATAF provided from the hierarchical video encoding device 2 or hierarchical encoded data DATAAR provided from the encoded data conversion device 3). Decoding is performed to generate a decoded image POUT # T of the target layer. In the following description, it is assumed that the target layer is an extension layer having the base layer as a reference layer. Therefore, the target layer is also an upper layer with respect to the reference layer. Conversely, the reference layer is also a lower layer with respect to the target layer.

  As illustrated in FIG. 5, the hierarchical video decoding device 1 includes a NAL demultiplexing unit 11, a parameter set decoding unit 12, a tile setting unit 13, a slice decoding unit 14, a base decoding unit 15, and a decoded picture management unit 16.

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

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

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

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

  Hierarchical encoded data DATA includes NAL including parameter sets (VPS, SPS, PPS), SEI and the like in addition to NAL generated by VCL. Those NALs are called non-VCL NALs versus VCL NALs.

  The NAL demultiplexing unit 11 demultiplexes the hierarchical encoded data DATA, and extracts the target layer encoded data DATA # T and the reference layer encoded data DATA # R. Also, the NAL demultiplexing unit 11 supplies non-VCL NAL to the parameter set decoding unit 12 and VCL NAL to the slice decoding unit 14 among NALs included in the target layer encoded data DATA # T.

  The parameter set decoding unit 12 decodes the parameter set, that is, VPS, SPS, and PPS, from the input non-VCL NAL, and supplies them to the tile setting unit 13 and the slice decoding unit 14.

  The tile setting unit 13 derives picture tile information based on the input parameter set and supplies the derived tile information to the slice decoding unit 14. The tile information includes at least tile division information of a picture. The detailed description of the tile setting unit 13 will be described later.

  The slice decoding unit 14 generates a decoded picture or a partial area of the decoded picture based on the input VCL NAL, parameter set, tile information, and reference picture, and records the decoded picture in a buffer in the decoded picture management unit 16. . A detailed description of the slice decoding unit will be described later.

  The decoded picture management unit 16 records an input decoded picture and a base decoded picture in an internal decoded picture buffer (DPB), and generates a reference picture list and determines an output picture. Also, the decoded picture management unit 16 outputs the decoded picture recorded in the DPB to the outside as an output picture POUT # T at a predetermined timing.

  The base decoding unit 15 decodes a base decoded picture from the reference layer encoded data DATA # R. The base decoded picture is a decoded picture of the reference layer used when decoding the decoded picture of the target layer. The base decoding unit 15 records the decoded base decoded picture in the DPB in the decoded picture management unit 16.

  The detailed configuration of the base decoding unit 15 will be described with reference to FIG. FIG. 6 is a functional block diagram illustrating the configuration of the base decoding unit 15.

  As shown in FIG. 6, the base decoding unit 15 includes a base NAL demultiplexing unit 151, a base parameter set decoding unit 152, a base tile setting unit 153, a base slice decoding unit 154, and a base decoded picture management unit 156.

  The base NAL demultiplexing unit 151 demultiplexes the reference layer encoded data DATA # R to extract the VCL NAL and the non-VCL NAL, the non-VCL NAL to the base parameter set decoding unit 152, and the VCL NAL to the base slice Each is supplied to the decryption unit 154.

  The base parameter set decoding unit 152 decodes the parameter set, that is, VPS, SPS, and PPS, from the input non-VCL NAL and supplies them to the base tile setting unit 153 and the base slice decoding unit 154.

  The base style setting unit 153 derives picture tile information based on the input parameter set and supplies the derived tile information to the base slice decoding unit 154.

  The base slice decoding unit 154 generates a decoded picture or a partial area of the decoded picture based on the input VCL NAL, parameter set, tile information, and reference picture, and stores the decoded picture in the buffer in the base decoded picture management unit 156. Record.

  The base decoded picture management unit 156 records the input decoded picture in the internal DPB, and performs reference picture list generation and output picture determination. Further, the base decoded picture management unit 156 outputs the decoded picture recorded in the DPB as a base decoded picture at a predetermined timing.

(Tile setting unit 13)
The tile setting unit 13 derives and outputs tile information of a picture based on the input parameter set.

  In the present embodiment, the tile information generated by the tile setting unit 13 schematically includes tile structure information and tile dependency information.

  The tile structure information is information indicating the number of tiles in the picture and the size of each tile. When the tile is associated with a partial area obtained by dividing the picture into a grid, the number of tiles in the picture is equal to the product of the number of tiles included in the horizontal direction and the number of tiles included in the vertical direction.

  The tile dependency information is information indicating dependency at the time of decoding a tile in a picture. Here, the dependency at the time of decoding the tile indicates the degree to which the tile depends on the decoded pixel and the syntax value related to the area outside the tile. Note that the area outside the tile includes an area outside the tile on the target picture, an area outside the tile on the reference picture, and an area outside the tile on the base decoded picture.

  Hereinafter, details of tile information generated by the tile setting unit 13 will be described including a derivation process based on an input parameter set.

  The tile information is derived based on the syntax value related to the tile information included in the SPS or PPS included in the parameter set. The syntax related to tile information will be described with reference to FIGS.

(PPS tile information)
FIG. 7 is a part of the syntax table referred to by the parameter decoding unit 12 when decoding the PPS included in the parameter set, and is a part related to tile information.

  The syntax (PPS tile information) related to tile information included in the PPS includes a multi-tile enabled flag (tiles_enabled_flag). When the value of the multi-tile valid flag is 1, it indicates that the picture is composed of two or more tiles. When the value of the flag is 0, the picture is composed of one tile, that is, the picture and the tile match.

  When multiple tiles are enabled (tiles_enabled_flag is true), the PPS tile information includes information indicating the number of tile columns (num_tile_columns_minus1), information indicating the number of tile rows (num_tiles_rows_minus1), and a flag indicating tile size uniformity ( uniform_spacing_flag) is additionally included.

  num_tile_columns_minus1 is a syntax corresponding to a value obtained by subtracting 1 from the number of tiles included in the horizontal direction of a picture. Num_tile_rows_minus1 is a syntax corresponding to a value obtained by subtracting 1 from the number of tiles included in the vertical direction of the picture. Therefore, the number of tiles NumTilesInPic included in the picture is calculated by the following equation.

NumTilesInPic = (num_tile_columns_minus1 + 1) * (num_tile_rows_minus1 + 1)
A uniform_spacing_flag value of 1 indicates that the tile size included in the picture is uniform, that is, the width and height of each tile are equal. A uniform_spacing_flag value of 0 indicates that the tile sizes included in the picture are uneven, that is, the width and height of the tiles included in the picture do not necessarily match.

  When the tile size included in the picture is uneven (uniform_spacing_flag is 0), the PPS tile information includes information indicating the tile width (column_width_minus1 [i]) for each tile column included in the picture, and the picture For each tile row included, additional information (row_height_minus1 [i]) indicating the height of the tile is included.

  Further, when a plurality of tiles are valid, the PPS tile information additionally includes a flag (loop_filter_across_tiles_enabled_flag) indicating whether or not to apply a loop filter that crosses the tile boundary.

  Here, the relationship between tile rows, tile columns, and pictures will be described with reference to FIG. FIG. 8 is a diagram illustrating tile rows and tile columns when a picture is divided into tiles. In the example of FIG. 8, the picture is divided by 4 tile columns and 3 tile rows, and includes a total of 12 tiles. For example, the tile row 0 (TileCol0) includes tiles T00, T10, and T20. For example, tile row 0 (TileRow0) includes tiles T00, T01, T02, and T03. The width of the tile row i is expressed as ColWidth [i] in CTU units. The height of the tile row j is expressed as RowHeight [j] in CTU units. Therefore, the width of the tile belonging to tile row i and belonging to tile column j is ColWidth [i] and the height is RowHeight [j].

  Based on the above PPS tile information, the tile setting unit 13 derives tile structure information. The tile structure information includes an array for deriving a tile scan CTB address from a raster scan CTB address (CtbAddrRsToTs [ctbAddrRs]), an array for deriving a raster scan CTB address from a tile scan CTB address (CtbAddrTsToRs [ctbAddrTs]), and a tile scan CTB address Each tile identifier (TileId [ctbAddrTs]), the width of each tile column (ColumnWidthInLumaSamples [i]), and the height of each tile row (RowHeightInLumaSamples [j]) are included.

  When uniform_spacing_flag is 1, the width of each tile column is calculated based on the picture size and the number of tiles in the picture. For example, the width of the i-th tile column (ColumnWidthInLumaSamples [i]) is calculated by the following equation. Note that PicWidthInCtbsY represents the number of CTUs included in the horizontal direction of the picture.

ColWidth [i] = ((i + 1) * PicWidthInCtbsY) / (num_tile_columns_minus1 + 1)-(i * PicWidthInCtbsY) / (num_tile_columns_minus1 + 1)
That is, ColWidth [i], which is the width of the i-th tile column in CTU units, is calculated as the difference between the (i + 1) -th and i-th boundary positions obtained by equally dividing the picture by the number of tile columns. .

  On the other hand, when uniform_spacing_flag is 0, the value of (column_width_minus1 [i] +1) is set to the width ColWidth [i] in CTU units of the i-th tile column.

  The value of ColumnWidthInLumaSamples [i] is set to the value obtained by multiplying ColWidth [i] by the width of the CTU pixel unit.

  Note that the height RowHeight [j] of tile rows in CTU units is also calculated in the same manner as the width of the tile row. PicHeightInCtbsY (the number of CTUs included in the vertical direction of the picture) is used instead of PicWidthInCtbsY, and num_tiles_row_minus1 and row_height_minus1 [i] are used instead of num_tiles_columns_minus1 and column_width_minus1 [i].

  The value of RowHeightInLumaSamples [j] is set to a value obtained by multiplying RowHeight [j] by the height of the CTU in pixel units.

  Next, a method for deriving an array (CtbAddrTsToRs [ctbAddrTs]) for deriving raster scan CTB addresses from tile scan CTB addresses will be described.

  First, colBd [i] indicating the boundary position of the i-th tile row and rowBd [j] indicating the boundary position of the j-th tile row are calculated by the following equations. Note that the values of colBd [0] and rowBd [0] are 0.

colBd [i + 1] = colBd [i] + colWidth [i]
rowBd [j + 1] = rowBd [j] + rowHeight [j]
Subsequently, the tile scan CTU address associated with the CTU identified by the raster scan CTU address (ctbAddrRs) included in the picture is derived by the following procedure.

  The position (tbX, tbY) in the CTU unit within the picture of the target CTU is calculated from ctbAddrRs by the following formula. Here, the operator “%” is a remainder operator, and “A% B” means a remainder obtained by dividing the integer A by the integer B.

tbX = ctbAddrRs% PicWidthInCtbsY
tbY = ctbAddrRs / PicWidthInCtbsY
Subsequently, the position (tileX, tileY) of the tile unit in the picture of the tile including the target CTU is derived. In tileX, the maximum value of i at which the evaluation formula (tbX> = colBd [i]) is true is set. Similarly, the maximum value of j for which the evaluation formula (tbY> = rowBd [j]) is true is set in tileY.

  The value of CtbAddrRsToTs [ctbAddrRs] includes the sum of the CTUs included in the tiles that precede the tiles of (tileX, tileY) in the tile scan order, and (tbX-colBd [tileX] within the tiles of (tileX, tileY), A value obtained by adding the positions of the raster scan order in the tile of the CTU located at tbY−rowBd [tileY]) is set.

  The value of k when CtbAddrRsToTs [k] matches ctbAddrTs is set to the value of CtbAddrTsToRs [ctbAddrTs].

  In the value of TileId [ctbAddrTs], the tile identifier of the tile to which the CTU indicated by ctbAddrTs belongs is set. The tile identifier tileId (tileX, tileY) of the tile located at the position of (tileX, tileY) in the tile in the picture is calculated by the following equation.

tileId (tileX, tileY) = (tileY * (num_tile_cols_minus1 + 1)) + tileX
(SPS tile information)
FIG. 9 is a part of the syntax table that is referred to by the parameter decoding unit 12 when decoding the SPS included in the parameter set, and is a part related to tile information. The SPS extension (sps_extension) included in the SPS of the upper layer includes an all tile dependency identifier (all_tiles_decoding_dependency_idc) as tile dependency information.

  The all-tile dependency identifier value includes dependency information related to decoding of all tiles included in the encoded data. Specifically, it includes information on motion dependence and inter-layer dependence.

  In the motion prediction, inter-prediction in a layer is a decoded pixel of a region (region outside the reference picture tile) that is not included in the region on the reference picture (corresponding tile region on the reference picture) at the same position as each tile of the target picture. And whether the tile of the target picture can be decoded without depending on the syntax of the region outside the reference picture tile. In the following, a case where a tile can be decoded without depending on a decoded pixel or syntax in a region outside the reference picture tile is expressed as “no motion dependency”, and the other case is expressed as “motion dependency”.

  Inter-layer dependence is an area that is not included in the area on the inter-layer reference picture (corresponding tile area on the inter-layer reference picture) that is in the same position as each tile of the target picture in inter-layer prediction (outside the inter-layer reference picture tile) This indicates whether or not the tile of the target picture can be decoded without depending on the decoded pixel in the region) and the syntax of the region outside the reference picture tile between the layers. In the following, when the tile can be decoded without depending on the decoded pixel or syntax of the inter-layer reference picture tile non-region area, “no inter-layer dependency”, otherwise “inter-layer dependency” Express.

  FIG. 10 shows the correspondence between all layer dependency identifier values, motion dependency, and inter-layer dependency. As shown in FIG. 10, the value 0 of the all layer dependency identifier indicates that there is both motion dependency and inter-layer dependency. A value 1 of all layer dependency identifiers indicates that there is motion dependency and no inter-layer dependency. The value 2 of the all layer dependency identifier indicates that there is no motion dependency and inter-layer dependency. A value 3 of all layer dependency identifiers indicates that neither motion dependency nor inter-layer dependency exists.

  According to the above correspondence relationship, when the value of the all layer dependency identifier is expressed in binary, the lower 1 bit corresponds to the presence / absence of inter-layer dependency, and the upper 1 bit corresponds to the presence / absence of motion dependency. The relationship between the value of all layer dependency identifiers, motion dependency, and inter-layer dependency is not limited to the above correspondence relationship. However, if the above correspondence relationship is used, it is possible to determine whether there is dependency only for motion dependency or only for inter-layer dependency. This is preferable because it can be easily determined.

  Note that the tile-dependent information is not necessarily included in the SPS, and may be included in another parameter set, for example, VPS or PPS.

  Further, the all layer dependency identifier has been described as the tile dependency information, but other information may be used as the tile dependency information. More generally, if any of the following information is included, it can be used as tile-dependent information.

(1) Information indicating whether or not to refer to the decoded pixel in the non-tile area on the reference picture when decoding an arbitrary tile (2) The encoding parameter (eg, motion information) of the non-tile area on the reference picture when decoding an arbitrary tile (3) Information indicating whether to refer to the decoded pixel in the area outside the tile on the inter-layer reference picture at the time of arbitrary tile decoding (4) Reference between layers at the time of arbitrary tile decoding Information indicating whether or not to refer to an encoding parameter (for example, motion information) of an area outside a tile on a picture. For example, a binary flag, and information indicating the above (1) can be used as tile-dependent information. Further, for example, in the case of ternary information, “0” indicates that the decoded pixel in the non-tile area is referred to in (1) above, and “1” indicates the decoded pixel in the non-tile area in (1) above. In the above (2), reference is made to the encoding parameter of the area outside the tile, and “2” does not refer to the decoded pixel in the area outside the tile in (1), and Information indicating that the encoding parameter of the non-tile area is not referred to may be used as the tile-dependent information.

(Slice decoding unit 14)
The slice decoding unit 14 generates and outputs a decoded picture based on the input VCL NAL, parameter set, and tile information.

  A schematic configuration of the slice decoding unit 14 will be described with reference to FIG. FIG. 11 is a functional block diagram illustrating a schematic configuration of the slice decoding unit 14.

  The slice decoding unit 14 includes a slice header decoding unit 141, a slice position setting unit 142, a skip slice determination unit 143, and a CTU decoding unit 144. The CTU decoding unit 144 further includes a non-skip CTU decoding unit 144N and a skip CTU generation unit 144S.

(Slice header decoding unit)
The slice header decoding unit 141 decodes the slice header based on the input VCL NAL and the parameter set, and outputs the decoded slice header to the slice position setting unit 142, the skip slice determination unit 143, and the CTU decoding unit 144.

  The slice header includes information related to the slice position in the picture (SH slice position information) and information related to the skip slice (SH skip slice information). Hereinafter, a syntax table that the slice header decoding unit 141 refers to during slice header decoding will be described as an example.

  FIG. 12 shows a part of the syntax table referenced by the slice header decoding unit 141 at the time of decoding the slice header, and is a part related to the slice position information.

  The slice header includes an in-picture first slice flag (first_slice_segment_in_pic_flag) as slice position information. When the in-picture head slice flag is 1, it indicates that the target slice is located at the head in the picture in decoding order. When the in-picture head slice flag is 0, it indicates that the target slice is not located at the head in the picture in decoding order.

  The slice header includes a slice PPS identifier (slice_pic_parameter_set_id) as slice position information. The slice PPS identifier is an identifier of a PPS associated with the target slice, and tile information to be associated with the target slice is specified via the PPS identifier.

  The slice header includes a slice segment address (slice_segment_address) as slice position information. The slice segment address is information that designates the position of the target slice, that is, the position in the picture of the first CTU in the decoding order among the CTUs included in the target slice, by an address in the CTU raster scan order in the picture.

  FIG. 13 is a part of the syntax table referred to by the slice header decoding unit 141 at the time of slice header decoding, and is a part related to skip slice information.

  The skip slice information is a slice header included in an upper layer, and is decoded when slice header extension is valid (slice_segment_header_extension_present_flag is true). Accordingly, skip slice information is not included in the slice header in a base layer that cannot be an upper layer.

  When multiple tiles are enabled (tiles_enabled_flag is true) and all tile dependency identifiers indicate at least one of motion dependency and inter-layer dependency (all_tiles_decoding_dependency_idc> 0), the slice header contains a skip slice The information includes a non-important tile flag (non_significant_tile_flag). Furthermore, when the non-important tile flag is true, a syntax (num_ctu_in_slice_segment_minus1) indicating the number of CTUs included in the slice is included. The syntax representing the number of CTUs included in the slice is also referred to as a skip CTU number. Note that the non-important tile flag is also referred to as a skip slice flag. Moreover, it is preferable that the value of the non-important tile flag included in the same tile is limited so as to match.

  Here, num_ctu_in_slice_segment_minus1 is decoded as a binarized non-negative integer having a bit length M. The bit length M is calculated by the following formula based on the number of CTUs included in the tile including the target slice.

M = Ceil (Log2 (ColWidth [tileX] * RowHeight [tileY])
Where tileX = tileIdx% (num_tile_cols_minus1 + 1)
tileY = tileIdx / (num_tile_cols_minus1 + 1)
tileIdx = TileId [CtbAddrRsToTs [slice_segment_address]]
The value of M derived according to the above formula is Ceil (K), where K is the logarithm of 2 of the CTU number (ColWidth [tileX] * RowHeight [tileY]) included in the tile corresponding to the tile identifier tileIdx. That is, it is a value corresponding to the smallest integer among the integers of K or more.

  Note that num_ctu_in_slice_segment_minus1 may be binarized by a method other than the above. For example, the integer N may be set to N = Ceil (Log2 (numCtbsInPics)) using the number of CTUs numCtbsInPics included in the picture, and binarized as a non-negative integer having the bit length as N. However, in general, when a plurality of tiles are used, since the slice is included in the tile, when transmitting num_ctu_in_slice_segment_minus1, the number of CTUs included in the slice does not exceed the number of CTUs included in the tile. Therefore, it is preferable to use a code length based on the number of CTUs included in tiles smaller than the number of CTUs included in the picture, because the syntax can be encoded with a smaller code amount.

  The skip slice information included in the slice header described with reference to FIG. 13 can also be expressed as follows. That is, the slice header of the base layer does not include skip slice information, and the slice header of the upper layer includes skip slice information under a predetermined condition.

  Adding the skip slice information only to the slice header of the upper layer in this way is particularly useful when the base layer conforms to an existing standard such as HEVC. This is because HEVC is already popular and it is difficult to change the syntax of the slice header. In such a case, by adding skip slice information only to the upper layer under a predetermined condition, the upper layer is an application represented by a high-resolution image display of the attention area without impairing the backward compatibility of the base layer. A skip slice function that can be used can be provided.

(Slice position setting part)
The slice position setting unit 142 specifies the slice position in the picture based on the input slice header and tile information, and outputs the slice position to the CTU decoding unit 144.

  When the position in the picture of the i-th CTU in the slice is described in CTU units (ctbX [i], ctbY [i]) and the address by tile scan is described as ctbAddrTs [i], the first CTU of the slice, that is, 0 The position (ctbX [0], ctbY [0]) in the picture of the th CTU and the address ctbAddrTs by tile scanning are calculated by the following equations.

ctbAddrTs [0] = CtbAddrRsToTs [slice_segment_address]
ctbX [0] = slice_segment_address% PicWidthInCtbsY
ctbY [0] = slice_segment_address / PicWidthInCtbsY
Here, CtbAddrRsToTs [X] is an array for converting raster scan addresses into tile scan addresses, and is included in tile information input to the slice position setting unit.

  Further, the position (ctbX [i], ctbY [i]) in the picture of the i-th (i> 0) CTU in the slice is calculated by the following equation.

ctbAddrTs [i] = ctbAddrTs [i-1] + 1
ctbX [i] = CtbAddrTsToRs [ctbAddrTs [i]]% PicWidthInCtbsY
ctbY [i] = CtbAddrTsToRs [ctbAddrTs [i]] / PicWidthInCtbsY
That is, the tile scan address of the target CTU is set to a value obtained by adding 1 to the tile scan address of the immediately preceding CTU. The obtained tile scan address is converted into a raster scan address using the conversion array CtbAddrTsToRs included in the tile information. The position (ctbX [i], ctbY [i]) in the CTU picture is derived from the raster scan address and the picture width in CTU units.

  To calculate the position (ctbXInLumaPixels [i], ctbYInLumaPixels [i]) of the CTU in the picture's luminance pixel unit from (ctbX [i], ctbY [i]), calculate by multiplying each element by the CTU size. do it. For example, it can be calculated as follows using CtbLog2SizeY which is the logarithm of 2 of the CTU width in luminance pixel units.

ctbXInLumaPixels [i] = ctbX [i] << CtbLog2SizeY
ctbYInLumaPixels [i] = ctbY [i] << CtbLog2SizeY
Through the above processing, the slice position setting unit 142 calculates and outputs the position of each CTU included in the slice in the picture.

(Skip slice determination unit)
The skip slice determination unit 143 determines whether the target slice is a skip slice based on the input slice header. When it is determined that the target slice is a skip slice, the slice header is output to the skip CTU generation unit 144S in the CTU decoding unit 144. When it is determined that the target slice is a non-skip slice, the slice header and the slice data are output to the non-skip CTU decoding unit 144N in the CTU decoding unit 144.

  Processing for determining whether or not the target slice is a skip slice, executed by the skip slice determination unit 143, will be described with reference to FIG. FIG. 1 is a flowchart of processing for determining whether or not a target slice is a skip slice. The determination of the skip slice is executed according to the following steps S101 to S105.

  (S101) If the number of tiles in the picture is 2 or more (YES in S101), the process proceeds to S102. Otherwise (NO in S101), the process proceeds to S105. Note that the determination in S101 can be performed with reference to the value of tiles_enabled_flag. That is, it can be determined using the fact that if the value of tiles_enabled_flag is 1, the number of tiles in the picture is 2 or more, and if the value of tiles_enabled_flag is 0, the number of tiles in the picture is 1.

  (S102) If there is no motion dependency or inter-layer dependency for all tiles included in the sequence (YES in S102), the process proceeds to S103. Otherwise (NO in S102), the process proceeds to S105. Note that the determination in S102 can be performed with reference to the all-tiles dependency identifier (all_tiles_decoding_dependency_idc) included in the SPS tile information described above.

  (S103) If the value of the non-important tile flag (non_significant_tile_flag) is equal to 1 (YES in S103), the process proceeds to S104. Otherwise (NO in S103), the process proceeds to S105.

  (S104) The target slice is set as a skip slice and the process is terminated.

  (S105) The target slice is set as a non-skip slice and the process is terminated.

  According to the above procedure, if the condition that the non-important tile does not exist (the number of tiles in the picture is 1 or both the motion information and the inter-layer dependence depend) is satisfied, the target slice is a non-skip slice. In other cases, whether the target slice is a non-skip slice or a skip slice is determined according to the value of the non-important tile flag.

  According to the above procedure, skipping of tiles can be suppressed when the number of tiles in a picture is 1. The usefulness of processing that uses the entire upper layer picture as a skip slice is low. This is because in such a case, it can be substituted by decoding only the lower layer. Therefore, it is preferable that the process of skipping tiles when the number of tiles is 1 can be suppressed.

  Moreover, according to said procedure, it can suppress that a tile is skipped when there exists both motion dependence and inter-layer dependence. When there is motion dependence, there is a possibility that a pixel value or syntax value outside the region corresponding to the same position as the tile on the reference picture is referred to in decoding the tile to which the target slice belongs. Therefore, it is not preferable to encode a tile outside the attention area as a skip slice because a decoded image in the attention area in the subsequent picture is affected. In addition, when there is inter-layer dependency, it is necessary to decode lower layer tiles corresponding to tiles outside the attention area, and reduce complexity without decoding areas outside the attention area in the lower layer, This is not preferable because the tile corresponding to the attention area of the layer and the tile of the target layer cannot be decoded in parallel. Therefore, it is preferable that tiles can be skipped only when there is no interdependence between motion and inter-layer dependence, and such a restriction can be realized by the procedure of S102 described above.

  In the process described with reference to FIG. 1, the determination process related to the number of tiles in S101 may be omitted, and the process may be performed assuming that YES is selected in S101. In that case, there is a possibility that the entire picture is skipped, but the amount of determination processing can be reduced.

  In addition, in the process described with reference to FIG. 1, instead of the process in S102, that is, the process of determining whether “all tiles have no motion dependency or all tiles have no inter-layer dependency”, You may perform the process which determines whether a tile has no motion dependence. Such a configuration is particularly effective when the target layer is not a reference layer, and can reduce the determination process. This is because even if the tile of the target layer is changed to a skip slice, there is no possibility that the tile is referred to by inter-layer prediction in a higher layer.

  Note that the process shown in FIG. 14 may be used instead of the process described with reference to FIG. In FIG. 14, the flow of FIG. 1 is that if the determination processing of S101 and S102 in FIG. 1 is NO, the target slice is not directly set as a non-skip slice, but S106a is set once to set the value of non_significant_flag to 0. And different. The determination of the skip slice based on FIG. 14 is executed in the following steps S101a to S106. Note that the processing of S103, S104, and S105 is the same as the processing of the same reference numerals described with reference to FIG.

  (S101a) If the number of tiles in the picture is 2 or more (YES in S101a), the process proceeds to S102a. Otherwise (NO in S101a), the process proceeds to S106a.

  (S102a) When there is no motion dependency or inter-layer dependency for all tiles included in the sequence (YES in S102a), the process proceeds to S103. In other cases (NO in S102a), the process proceeds to S106a.

  (S106a) The value of the non-important tile flag (non_significant_tile_flag) is set to 0, and the process proceeds to S103.

  The determination process of whether or not the target slice described with reference to FIG. 14 is a skip slice has an advantage that it can be implemented with a smaller number of determinations than the process described with reference to FIG. This is because the number of tiles in a picture can be determined by PPS tile information. That is, the determination in S101a can be executed once for each PPS and the result can be saved. Further, the all-tile dependency identifier used for the determination in S102a is included in the SPS tile information. That is, the determination in S102a can be executed once for each SPS and the result can be saved.

  In addition, when decoding non_significant_tile_flag based on the syntax table shown in FIG. 13, setting the estimated value when non_significant_tile_flag does not exist in the encoded data is set to 0, The same skip slice determination process can be realized. This is because, in the syntax table of FIG. 13, non_significant_tile_flag is decoded only when S101a is YES (tiles_enabled_flag is 1) and S101b is YES (all_tiles_decoding_dependency_idc> 0).

(CTU decoder)
In general, the CTU decoding unit 144 decodes a slice by decoding a decoded image in a region corresponding to each CTU included in the slice based on the input slice header, slice data, and parameter set. Generate an image. The decoded image of the slice is output as a part of the decoded picture at the position indicated by the input slice position. The decoded image of the CTU is executed by the non-skip CTU decoding unit 144N or the skip CTU generation unit 144S included in the CTU decoding unit 144 based on the result of the skip slice determination unit 143.

  The non-skip CTU decoding unit 144N decodes and outputs the decoded image of the CTU included in the non-skip slice based on the input slice header and slice data. That is, the prediction information of the target CTU is generated by decoding the PT information included in the slice data, the prediction residual of the target CTU is generated by decoding the TT information included in the slice data, and the prediction image and the prediction residual Based on the above, a decoded image of the target CTU is generated.

(Skip CTU generator)
The skip CTU generation unit 144S decodes and outputs the decoded image of the CTU included in the skip slice based on the input slice header. The pixel value p (x, y) of the decoded image of the CTU generated by the skip CTU generation unit 144S can be generated by the following equation, for example. Here, (x, y) represents the pixel position in the CTU, and BitDepth represents the bit depth of the output image.

p (x, y) = 1 << (BitDepth-1)
In other words, the pixel value of the decoded image is set to a fixed value (a value obtained by adding 1 to the maximum value expressed by the bit depth divided by 2) depending on the bit depth regardless of the position in the CTU. The For example, when the bit depth of the output image is 8 bits, a value of 128 is set as the decoded pixel value of each pixel in the skip CTU.

  Note that the method for generating the pixel value of the decoded image is not necessarily the method described above. The pixel value of the decoded image may be derived by another generation method that does not depend on slice data. For example, when the parameter set indicates that the decoded pixel of the reference picture or the inter-layer reference picture can be referred to, the decoded pixel on the reference picture or the inter-layer reference picture may be copied and used as the pixel value of the skip CTU. When using an inter-layer reference picture, the decoded image may be copied after scaling as necessary.

(Slice decoding process flow)
The slice decoding process in the slice decoding unit 14 will be described with reference to FIG. FIG. 15 is a flowchart showing a procedure of slice decoding processing.

  (S201) The slice header decoding unit 141 decodes the slice header from the VLC NAL based on the parameter set. The slice header is output to the slice position setting unit 142, and the slice header and the slice data included in the VLC NAL are output to the skip slice determination unit. The process proceeds to S202.

  (S202) The slice position setting unit 142 derives a slice position based on the tile information and the slice header, and outputs the slice position to the CTU decoding unit 144. The process proceeds to S203.

  (S203) The skip slice determination unit 143 determines whether the target slice is a skip slice or a non-skip slice based on the slice header. If the target slice is a non-skip slice, the slice header and slice data are output to the non-skip CTU decoding unit 144N, and the process proceeds to S204a. If the target slice is a skip slice, the slice header is output to the skip CTU generation unit 144S, and the process proceeds to S204b.

  (S204a) The non-skip slice CTU decoding unit 144N sequentially decodes the CTU from the slice data, and outputs the decoded image of the CTU as a partial region of a decoded picture corresponding to the position indicated by the input slice position. The process proceeds to S205.

  (S204b) The skip slice CTU generating unit 144S generates a decoded image of the number of CTUs indicated by the slice header by a predetermined derivation process, and the decoded picture of the generated CTU is a decoded picture corresponding to the position indicated by the input slice position. Is output as a partial area. The process proceeds to S205.

  (S205) The CTU decoding unit 144 outputs the decoded image of the CTU included in the slice output from the non-skip CTU decoding unit 144N or the skip CTU generation unit 144S as a decoded image of a slice that is a part of the decoded picture.

(Effect of moving image decoding apparatus 1)
The hierarchical moving picture decoding apparatus 1 (hierarchical picture decoding apparatus) according to the present embodiment described above decodes the upper layer encoded data included in the hierarchically encoded data, and restores the upper layer decoded picture. A slice header decoding unit 141 that decodes a slice header of an upper layer, and a non-skip CTU decoding unit 144N that decodes a decoded image of a CTU belonging to a non-skip slice of the upper layer based on slice data A skip CTU generation unit 144S that generates a decoded image of the CTU belonging to the skip slice of the upper layer is provided. The slice header decoding unit 141 decodes or estimates a skip slice flag indicating whether the target slice is a skip slice or a non-skip slice, and if the skip slice flag indicates that the target slice is a skip slice, a slice header decoding unit 141 decodes the number of skip CTUs and generates a decoded image of the target slice by generating decoded images of the number of CTUs indicated by the number of skipped CTUs by the skip CTU generation unit 144S. When the skip slice flag indicates that the target slice is a non-skip slice, a decoded image of the target slice can be generated by decoding the CTU included in the target slice by the non-skip CTU decoding unit 144N.

  As described above, when the value of the skip slice flag included in the upper layer slice header indicates that the target slice is a skip slice, the hierarchical video decoding device 1 according to the present invention skips CTU without using slice data. The generation unit can generate a decoded image in the target slice. Since the skip CTU generation unit generates the decoded image without using the slice data, the image quality of the decoded image is lower than when the non-skip CTU generation unit decodes the decoded image with reference to the slice data, but less processing is performed. A decoded image can be generated using a small amount of encoded data in an amount. Therefore, when the hierarchical video decoding device 1 decodes hierarchically encoded data that is encoded with a slice in a region included in the region of interest as a non-skip slice and a slice in a region not included in the region of interest as a skip slice In addition, a decoded image can be generated with a small processing amount from encoded data with a small code amount and output as a decoded picture without deteriorating the quality of the decoded image in the region of interest.

[Variation 1: Display by conformance window]
In the hierarchical video decoding apparatus 1 according to the present embodiment, a configuration will be described in which display area information is decoded from a parameter set, and a partial area of a decoded picture indicated by the display area information is output to the outside as a final output picture. In this configuration, display area information decoded from the parameter set is limited to an area that is a partial area of a decoded picture and does not include a skip slice. Hereinafter, a specific configuration and procedure will be described.

  The parameter set decoding unit 12 decodes the display area information from the input target layer encoded data DATA # T. The display area information is included in the SPS, for example, and is decoded according to the syntax table shown in FIG. FIG. 16 is a part of a syntax table that the parameter set decoding unit 12 refers to when performing SPS decoding, and is a part related to display area information.

  The display area information decoded from the SPS includes a display area flag (conformance_flag). The display area flag indicates whether information indicating the position of the display area (display area position information) is additionally included in the SPS. That is, when the display area flag is 1, it indicates that the display area position information is additionally included, and when the display area flag is 0, it indicates that the display area position information is not additionally included.

  When the display area flag is 1, the display area information decoded from the SPS further includes display area left offset (conf_win_left_offset), display area right offset (conf_win_right_offset), display area upper offset (conf_win_top_offset), and display area. Contains the lower offset (conf_win_bottom_offset).

  When the display area flag is 0, the entire picture is set as the display area. On the other hand, when the display area flag is 1, a partial area in the picture indicated by the display area position information is set. The display area is also referred to as a conformance window.

  The relationship between the display area position information and the display area will be described with reference to FIG. FIG. 17 is a diagram illustrating a relationship between a display area which is a partial area in a picture and display area position information. As shown in the figure, the display area is included in the picture, the display area offset is the distance between the picture upper edge and the display area upper edge, the display area left offset is the distance between the picture left edge and the display area left edge, and the display area right offset. Represents the distance between the right side of the picture and the right side of the display area, and the lower offset of the display area represents the distance between the lower side of the picture and the lower side of the display area. Therefore, the position and size of the display area in the picture can be uniquely specified by the display area position information. The display area information may be other information that can uniquely identify the position and size of the display area in the picture.

  The display area is limited so as not to include an area corresponding to a skip slice. In other words, the display area specified by the display area position information decoded from the parameter set is limited so as not to include a skip slice. Since the decoded image of the skip slice is generally lower in image quality than the decoded image of the skip slice, the image quality of the partial area of the decoded picture output from the hierarchical video decoding apparatus is limited by limiting the display area to the non-skip slice. Can be kept high.

  In general, the determination of the position of a slice in a picture is more difficult than the determination of the position in a tile picture. This is because the tile position can be calculated from the PPS, but the slice position (the position of each CTU included in the slice) cannot be specified until the slice header and slice data are decoded. Therefore, if the display area does not include the area corresponding to the tile including the skip slice, does the display area satisfy the constraints more easily than when the display area does not include the skip slice? You can determine whether or not.

  Note that in a configuration that does not output an area corresponding to a skip slice and that does not refer to an area corresponding to a skip slice, a configuration that does not include the skip CTU generation unit 144S may be possible. In this case, in the configuration in which the display area does not include the area corresponding to the tile including the skip slice and is not referred to, the decoded image derivation of the skip slice portion in the skip CTU generation unit 144S can be omitted. The amount of processing can be reduced.

(Configuration of Hierarchical Video Encoding Device)
A schematic configuration of the hierarchical video encoding device 2 will be described with reference to FIG. FIG. 18 is a functional block diagram showing a schematic configuration of the hierarchical video encoding device 2. The hierarchical video encoding device 2 encodes the input image PIN # T of the target layer with reference to the reference layer encoded data DATA # R to generate hierarchical encoded data DATA of the target layer. It is assumed that the reference layer encoded data DATA # R has been encoded in the hierarchical video encoding apparatus corresponding to the reference layer.

  As shown in FIG. 18, the hierarchical video encoding device 2 includes a NAL multiplexing unit 21, a parameter set encoding unit 22, a tile setting unit 23, a slice encoding unit 14, a decoded picture management unit 16, and a base decoding unit. 15.

  The NAL multiplexer 21 generates NAL-multiplexed hierarchical moving image encoded data DATA by storing the input target layer encoded data DATA # T and reference layer encoded data DATA # R in the NAL unit. And output to the outside.

  The parameter set encoding unit 22 sets parameter sets (VPS, SPS, and PPS) used for encoding the input image based on the input tile information and the input image, and sets the target layer encoded data DATA #. Packetized in the VCL NAL format as a part of T and supplied to the NAL multiplexer 21.

  The parameter set encoding unit 22 preferably includes display area information described with reference to FIGS. 16 and 17. Further, as described as the configuration of the modification 1 of the hierarchical video decoding device 1, it is preferable that the display area information is limited so as not to include an area corresponding to the skip slice. Alternatively, the display area information is preferably limited so as not to include an area corresponding to a tile including a skip slice.

  The tile setting unit 23 sets tile information of a picture based on the input image, and supplies it to the parameter set encoding unit 22 and the slice encoding unit 24. For example, tile information indicating that the picture size is divided into M × N tiles is set. Here, M and N are arbitrary positive integers. Further, for example, the tile information may be set so that the picture is divided into tiles of a predetermined size (for example, tiles of 128 pixels × 128 pixels).

  Based on the input image, parameter set, tile information, and reference picture recorded in the decoded picture management unit 16, the slice encoding unit 24 is a part of the input image corresponding to the slice constituting the picture. Is encoded to generate encoded data of the part, and the encoded data is supplied to the NAL multiplexer 21 as a part of the target layer encoded data DATA # T. Detailed description of the slice encoding unit 24 will be described later.

  The decoded picture management unit 16 is the same component as the decoded picture management unit 16 included in the hierarchical video decoding device 1 already described. However, since the decoded picture management unit 16 included in the hierarchical video encoding device 2 does not need to output the picture recorded in the internal DPB as an output picture, the output can be omitted. Note that the description described as “decoding” in the description of the decoded picture management unit 16 of the hierarchical video decoding device 1 is also applied to the decoded picture management unit 16 of the hierarchical video encoding device 2 by replacing “coding”. it can.

  The base decoding unit 15 is the same component as the base decoding unit 15 included in the hierarchical video decoding device 1 described above, and detailed description thereof is omitted.

(Slice coding unit)
Next, the details of the configuration of the slice encoding unit 24 will be described with reference to FIG. FIG. 19 is a functional block diagram showing a schematic configuration of the slice encoding unit 24.

  As illustrated in FIG. 19, the slice encoding unit 24 includes a slice header setting unit 241, a slice position setting unit 242, a skip slice determination unit 243, and a CTU encoding unit 244. The CTU encoding unit 244 includes a non-skip CTU encoding unit 244N and a skip CTU generation unit 244S inside.

  The slice header setting unit 241 generates a slice header used for encoding an input image input in units of slices based on the input parameter set and slice position information. The generated slice header is output as a part of the slice encoded data, and is supplied to the skip slice determination unit 143 together with the input image.

  The slice header generated by the slice header setting unit 241 includes at least the SH slice position information described with reference to FIG. 12 and the slice skip information described with reference to FIG.

  The slice position setting unit 242 determines a slice position in the picture based on the input tile information and supplies the slice position to the slice header setting unit 241.

  The skip slice setting unit 243 is a component corresponding to the skip slice determination unit 143 included in the slice decoding unit 14 of the hierarchical video decoding device 1, and based on the input slice header, whether or not the target slice is a skip slice Determine whether. The same determination criteria as the skip slice determination unit 143 can be used for the determination in the skip slice determination unit 243. When the target slice is determined to be a skip slice, the skip slice determination unit 243 outputs the slice header to the skip CTU generation unit 244S in the CTU encoding unit 244. When it is determined that the target slice is a non-skip slice, the slice header and the input image (target slice portion) are output to the non-skip CTU encoding unit 244N in the CTU encoding unit 244.

  The CTU encoding unit 244 encodes an input image (target slice portion) in units of CTU based on the input parameter set and slice header, and generates slice data and a decoded image (decoded picture) related to the target slice. Output. The CTU encoding is performed by either the non-skip CTU encoding unit 244N or the skip CTU generation unit 244S according to the determination result of the skip slice determination unit 243.

  The non-skip CTU encoding unit 244N generates the partial data of the corresponding slice data and the decoded image of the CTU by encoding the CTU included in the non-skip slice. In encoding, first, the prediction parameter (PT information) of the target CTU is derived based on the properties of the input image. Next, a prediction image of the target CTU is generated based on the prediction parameter, and a difference between the input image and the prediction image is generated as prediction residual information (TT information). The partial information of slice data corresponding to the target CTU is generated by combining the PT information and the TT information, and the prediction residual of the target CTU is generated by decoding the TT information. Based on the prediction image and the prediction residual Generate a decoded image of the target CTU.

  The skip CTU generation unit 244S decodes and outputs the decoded image of the CTU included in the skip slice based on the input slice header. The same processing as the skip CTU generation unit 144S included in the slice decoding unit 14 of the hierarchical video decoding device 1 can be used for the decoding image generation processing of the skip CTU generation unit 244S.

(Effect of moving picture coding apparatus 2)
The hierarchical video encoding device 2 according to the present embodiment described above is a hierarchical video encoding device (hierarchical image encoding device) that generates encoded data of an upper layer from an input image, and is a slice of an upper layer. A slice header encoding unit 24 that encodes a header, a non-skip CTU encoding unit 244N that encodes a decoded image of a CTU belonging to a non-skip slice of an upper layer based on slice data, and a skip slice of an upper layer A skip CTU generation unit 244S that generates a decoded image of the CTU is provided.

  Therefore, the hierarchical video encoding apparatus 2 according to the present invention can encode a region having a relatively low importance represented by a region outside the region of interest using a skip slice. In that case, the image quality of the decoded image is lower than when encoding using non-skip slices, but encoded data with a smaller code amount can be generated with a smaller amount of processing. Therefore, the hierarchical video encoding apparatus 2 encodes an input image by using a slice in a region included in the region of interest as a non-skip slice and a slice in a region not included in the region of interest as a skip slice, and generates hierarchical encoded data. In the case of generation, hierarchically encoded data with a small code amount can be generated without deteriorating the quality of the decoded image in the attention area.

  In addition, the hierarchical moving image encoding device 2 includes a parameter set encoding unit that encodes display area information, and the display area information is limited so as not to include tiles including skip slices. Therefore, even when the hierarchically encoded data encoded by the hierarchical moving image encoding device 2 is decoded and reproduced, it is possible to prevent the region corresponding to the decoded image with low quality from being reproduced. Can guarantee the quality of the playback image.

[Hierarchical coded data converter 3]
The schematic configuration of the hierarchically encoded data conversion device 3 will be described with reference to FIG. FIG. 20 is a functional block diagram showing a schematic configuration of the hierarchically encoded data conversion device 3. The hierarchical encoded data conversion device 3 converts the input hierarchical encoded data DATA to generate hierarchical encoded data DATA-ROI related to the input attention area information. The hierarchically encoded data DATA is hierarchically encoded data generated by the hierarchical moving image encoding device 2. Also, by inputting the hierarchically encoded data DATA-ROI to the hierarchical video decoding device 1, it is possible to reproduce the upper layer video related to the attention area information.

  As shown in FIG. 20, the hierarchical encoded data conversion apparatus 3 includes a NAL demultiplexing unit 11, a NAL multiplexing unit 21, a parameter set decoding unit 12, a tile setting unit 13, a parameter set correction unit 32, and a slice correction unit 34. including.

  Each of the NAL demultiplexing unit 11, the parameter set decoding unit 12, and the tile setting unit 13 has the same function as the component of the same name included in the hierarchical video decoding device 1, and therefore, the same reference numerals are given and description thereof is omitted. To do.

  Since the NAL multiplexing unit 21 has the same function as the component of the same name included in the hierarchical video encoding device 2, the same reference numeral is assigned and the description thereof is omitted.

  The parameter set correction unit 32 corrects and outputs the input parameter set information based on the input attention area information and tile information.

  The attention area information is a partial area of a picture specified by a user (for example, a viewer of a reproduction moving image) in a picture constituting the moving image. The attention area information is specified by a rectangular area, for example. In this case, for example, an offset of a position from the corresponding side (upper side, lower side, left side, or right side) of the entire picture of the upper side, the lower side, the left side, and the right side of the rectangle representing the target region can be designated as the attention region information. Note that an area having a shape other than a rectangle (for example, a circle, a polygon, or an area indicating an object extracted by object extraction) may be used as the attention area. However, for the sake of simplicity, a rectangular attention area is assumed below. To do. In addition, when the content described below is applied to a region other than a rectangle, for example, a rectangle with the smallest area including the region of interest can be regarded as the region of interest in the following description.

  The parameter set correction unit 32 rewrites the display area information of the SPS included in the input parameter set so as to match the attention area indicated by the input attention area information. When the syntax described with reference to FIG. 16 is used as the display area information of SPS, the display area information is rewritten by the following steps S301 to S303.

  (S301) It is determined whether or not the attention area matches the entire picture. If they match, the process proceeds to S302, and if they do not match, the process proceeds to S303.

  (S302) If the value of the display area flag before overwriting is 1, overwrite the value of the display area flag to 0 and remove the display area offset (conf_win_left_offset, conf_win_right_offset, conf_win_top_offset, conf_win_bottom_offset) from the SPS. To finish the process.

  (S303) The value of the display area flag is overwritten with 1. Each offset of the display area offset is set to the offset value of the position of each side of the rectangle representing the attention area with the corresponding side of the picture. For example, the position offset of the upper side of the attention area with respect to the upper side of the picture is set to the value of the display area upper offset (conf_win_top_offset). If the value of the display area flag before rewriting is 1, the original attention area offset value is overwritten using the attention area offset value set above. When the value of the display area flag before rewriting is 1, the set attention area offset is inserted immediately after the SPS display area flag.

  Based on the input parameter set and tile information, the slice correcting unit 34 corrects the input slice data to slice data considering the attention area information and outputs the slice data.

  In general, the slice data is corrected by setting a slice included in a tile that is not included in the region of interest as a skip slice, and a slice included in a tile including at least a portion of the region in the region of interest as a non-skip slice. It is a correction to set. The slice data correction process is executed according to the following steps S401 to S404.

  (S401) Each tile included in the picture is sequentially set as a target tile, and the following processes from S402 to S404 are executed.

  (S402) It is determined whether the target tile is completely outside the display area indicated by the display area information included in the SPS of the parameter set. For example, if all the conditions shown in C1 to C4 below are true, the target tile is determined to be outside the display area.

C1: The right side of the target tile matches the left side of the display area, or the former is located on the left of the latter.
C2: The left side of the target tile matches the right side of the display area, or the former is located on the right of the latter.
C3: The upper side of the target tile matches the lower side of the display area, or the former is located below the latter.
C4: The lower side of the target tile coincides with the upper side of the display area, or the former is positioned on the latter.

  If it is determined that the target tile is outside the display area, the process proceeds to S403. Otherwise, the process proceeds to S404.

  In the determination process, attention area information may be directly input to the slice correction unit 34 instead of the display area, and the attention area may be used instead of the display area.

  (S403) A slice included in the target tile is set as a skip slice. That is, the value of the skip slice flag included in the slice header is overwritten with 1 for all slices included in the target tile. When the value of the skip slice flag before overwriting is 0, the number of CTUs included in the slice is added as the number of skip CTUs immediately after the skip slice flag in the slice header, and all slice data is deleted.

  (S404) A slice included in the target tile is set as a non-skip slice. Normally, slice data before slice correction is a non-skip slice, and in this case, the input slice header and slice data are output as they are.

(Hierarchical coded data conversion process flow)
The hierarchical encoded data conversion process by the hierarchical encoded data conversion device 3 is realized by sequentially executing the procedures shown in S501 to S506.

  (S501) The NAL demultiplexing unit 11 demultiplexes the input hierarchical encoded data DATA. Of the obtained target layer encoded data DATA # T, the portion related to the parameter set (non-VCL NAL) is output to the parameter decoding unit 12, and the portion related to the slice layer (slice header, slice data) is output to the slice correction unit 34. Output to. The obtained reference layer encoded data DATA # R is output to the NAL demultiplexer 21.

  (S502) The parameter set decoding unit 12 decodes the parameter set (VPS, SPS, PPS) from the input non-VCL NAL and outputs it to the parameter set correction unit 32 and the tile setting unit 13.

  (S503) The parameter set correction unit 32 corrects the input parameter set based on the input attention area information, and outputs it to the NAL multiplexing unit 21 and the slice correction unit 34.

  (S504) The tile setting unit 13 derives tile information from the input parameter set and outputs the tile information to the slice correction unit 34.

  (S505) The slice correcting unit 34 corrects the input slice header and slice data based on the input tile information and the corrected parameter set, and outputs them to the NAL multiplexing unit 21.

  (S506) The NAL multiplexing unit 21 receives the input reference layer encoded data DATA # R as the encoded data of the target layer after correction of the corrected parameter set, the corrected slice header, and the slice data. And output to the outside as hierarchically encoded data DATA-ROI.

(Effect of Hierarchical Coded Data Conversion Device 3)
The hierarchical encoded data conversion device 3 according to the present embodiment described above includes the slice correction unit 34 that corrects the encoded data of the target layer (upper layer) based on the attention area information. Based on the attention area indicated by the attention area information, the slice correction unit 34 changes a slice that is included in the higher layer encoded data and is not included in the attention area from a non-skip slice to a skip slice.

  According to the above-described hierarchically encoded data conversion device 3, it is possible to convert the input hierarchically encoded data and generate hierarchically encoded data in which a slice not included in the attention area in the upper layer is converted into a skip slice. Since the skip slice has a smaller code amount than that of the non-skip slice, encoded data having a smaller code amount than before conversion can be generated. In addition, in the encoded data after conversion, since the region of interest is encoded with a non-skip slice, the image quality of the decoded image of the region of interest does not deteriorate compared to before conversion.

[Attention area display system]
A system that displays attention area information (attention area display system SYS) can be configured by combining the above-described hierarchical moving picture decoding apparatus 1, hierarchical moving picture encoding apparatus 2, and hierarchical encoded data conversion apparatus 3.

  Based on FIG. 21, it will be described that the attention area display system can be configured by a combination of the above-described hierarchical video decoding device 1, hierarchical video encoding device 2, and hierarchical encoded data conversion device 3. FIG. 21 is a block diagram illustrating a configuration of a region of interest display system that is a combination of the hierarchical video decoding device 1, the hierarchical video encoding device 2, and the hierarchical encoded data conversion device 3. The attention area display system SYS is generally provided by hierarchically encoding and storing input images having different qualities, and converting and providing the hierarchically encoded data accumulated according to attention area information from the user, By decoding the converted hierarchically encoded data, a high-quality reproduced image related to the region of interest (ROI) is displayed.

  As shown in FIG. 21, the attention area display system SYS includes a hierarchical video encoding unit SYS1A, a hierarchical video encoding unit SYS1B, a hierarchical encoded data storage unit SYS2, a hierarchical encoded data conversion unit SYS3, and a hierarchical video decoding. The unit SYS4, the display control unit SYS5, the ROI display unit SYS6, the whole display unit SYS7, and the ROI notification unit SYS8 are included as constituent elements.

  The above-described hierarchical video encoding device 2 can be used for the hierarchical video encoding units SYS1A and SYS1B.

  The hierarchically encoded data storage unit SYS2 stores hierarchically encoded data and supplies the hierarchically encoded data as required. A computer having a recording medium (memory, hard disk, optical disk) can be used as the hierarchically encoded data storage unit SYS2.

  The hierarchically encoded data conversion unit 3 described above can be used as the hierarchically encoded data conversion unit SYS3.

  The hierarchical video decoding device 1 can be used for the hierarchical video decoding unit SYS4.

  The display control unit SYS5 provides the decoded picture as the ROI display image to the ROI display unit SYS6 based on the attention area information, or supplies the decoded picture as the entire display image to the entire display unit SYS7.

  When the attention area is designated by the attention area information, the display control unit SYS5 supplies the whole picture display unit SYS7 with the decoded picture of the lower layer, which is a decoded picture input from the hierarchical moving picture decoding unit, as a whole display image. On the other hand, the ROI display unit SYS6 supplies the decoded picture input from the hierarchical moving image decoding unit and the decoded picture of the upper layer to the ROI display unit SYS6 as the ROI display image. Note that when the attention area is not specified in the attention area information, the ROI display image is not supplied to the ROI display section SYS6.

  When the attention area is designated by the attention area information, the display control unit SYS5 supplies the whole picture display unit SYS7 with the decoded picture of the lower layer, which is a decoded picture input from the hierarchical moving picture decoding unit, as a whole display image. On the other hand, the decoded picture is not supplied to the ROI display unit SYS6.

  Note that, when the attention area information is changed, the display control unit SYS5 is configured so that the decoded picture of the upper layer of the hierarchically encoded data related to the attention area information is supplied from the hierarchical video decoding unit SYS4. A partial region of the decoded picture in the lower layer of the encoded data and corresponding to the region of interest may be supplied to the ROI display unit SYS6 as the ROI display image. The partial area of the decoded picture of the lower layer, which corresponds to the attention area, has a lower image quality than the decoded picture of the upper layer related to the attention area. There is an advantage that the attention area can be displayed on the ROI display unit SYS6 without waiting for the delay accompanying the notification to the conversion unit and the conversion process.

  The ROI display unit SYS6 displays the ROI display image at a predetermined display position in a predetermined display area. For example, the display area is a television screen, and the display position is a partial area (for example, a rectangular area in the upper right corner). Further, for example, the display area is a display of a portable terminal (smart phone or tablet computer), and the display position is the whole.

  The entire display unit SYS7 displays the entire display image at a predetermined display position in a predetermined display area. For example, the display area is a television screen, and the display position is the whole. In addition, when the display area of whole display part SYS7 and ROI display part SYS6 is the same, it is preferable to display so that a ROI display image may be superimposed on a whole display image. Note that the ROI display unit SYS6 and the entire display unit SYS7 may display the input image enlarged or reduced to a size that matches the size of the display area.

  The ROI notification unit SYS8 notifies attention area information designated by the user by a predetermined method. For example, the user can inform the ROI notification unit of the attention area by designating an area corresponding to the attention area on the display area where the entire display image is displayed. Note that the ROI notification unit SYS8 notifies information indicating that there is no attention area as attention area information when there is no user designation.

(Flow of attention area display system)
Processing by the attention area display system can be divided into hierarchical encoded data generation and accumulation processing and attention area data generation and reproduction processing.

  In the hierarchically encoded data generation and accumulation process, hierarchically encoded data is generated and stored from input images of different qualities. The hierarchically encoded data generation / accumulation process is executed in the sequence from T101 to T103.

  (T101) The hierarchical moving image encoding unit SYS1B encodes the input low-quality input image, and supplies the generated hierarchical encoded data to the hierarchical moving image encoding unit SYS1A. That is, the hierarchical moving image encoding unit SYS1B generates and outputs hierarchical encoded data used as a reference layer (lower layer) in the hierarchical moving image encoding unit SYS1A from the input image.

  (T102) The hierarchical moving image encoding unit SYS1A encodes the input high-quality input image using the input hierarchical encoded data as encoded data of the reference layer, generates hierarchical encoded data, and generates a hierarchical code The data is output to the digitized data storage unit SYS2.

  (T103) The hierarchically encoded data storage unit SYS2 attaches an appropriate index to the input hierarchically encoded data and records it on an internal recording medium.

  In the attention area data generation / reproduction processing, the hierarchically encoded data is read from the hierarchically encoded data storage unit SYS2, converted into hierarchically encoded data corresponding to the attention area, and the converted hierarchically encoded data is decoded and reproduced and displayed. . The attention area data generation / reproduction processing is executed in the following steps T201 to T207.

  (T201) Hierarchical encoded data related to the moving image selected by the user is supplied from the hierarchically encoded data storage unit SYS2 to the hierarchically encoded data conversion unit SYS3.

  (T202) The ROI notification unit SYS8 notifies the attention area information designated by the user to the hierarchically encoded data conversion unit SYS3 and the display control unit SYS5.

  (T203) The hierarchical encoded data conversion unit SYS3 converts the input hierarchical encoded data based on the input attention area information, and outputs the converted hierarchical encoded data to the hierarchical video decoding unit SYS4.

  (T204) The hierarchical video decoding unit SYS4 decodes the input hierarchical video encoded data (after conversion), and outputs the reproduced decoded pictures of the upper layer and the lower layer to the display control unit SYS5.

  (T205) The display control unit SYS5 outputs the input decoded picture to the ROI display unit SYS6 and the entire display unit SYS7 based on the input attention area information.

  (T206) The entire display unit SYS7 displays the input entire display image.

  (T207) The ROI display unit SYS6 displays the input ROI display image.

(Effect of attention area display system)
The attention area display system SYS according to the present embodiment described above includes an attention area notification section (ROI notification section SYS8) that supplies attention area information, and converts the hierarchically encoded data based on the attention area information and after conversion. A hierarchical encoded data conversion unit SYS3 that generates hierarchical encoded data, a hierarchical moving image decoding unit SYS4 that decodes the converted hierarchical encoded data and outputs decoded pictures of an upper layer and a lower layer, and a display control unit SYS5 , An attention area display section (ROI display section SYS6), and an entire display section SYS7. The display control unit SYS5 supplies the lower layer decoded picture to the entire display unit SYS7, and supplies the upper layer decoded picture to the attention area display unit.

  According to the attention area display system SYS described above, the entire decoded picture of the lower layer can be displayed, and the decoded picture of the area specified by the attention area information can be displayed. At that time, the decoded picture of the area specified by the attention area information is decoded using the encoded data of the upper layer of the hierarchically encoded data, so that the image quality is high. In addition, the hierarchically encoded data converted based on the attention area has a smaller code amount than the hierarchically encoded data before conversion. Therefore, by using the attention area display system SYS described above, it is possible to reproduce a decoded picture with high image quality related to the attention area while reducing the bandwidth required for transferring the hierarchically encoded data.

(Application example to other hierarchical video encoding / decoding systems)
The above-described hierarchical video encoding device 2 and hierarchical video decoding device 1 can be used by being mounted on various devices that perform transmission, reception, recording, and reproduction of moving images. The moving image may be a natural moving image captured by a camera or the like, or may be an artificial moving image (including CG and GUI) generated by a computer or the like.

  Based on FIG. 22, it will be described that the above-described hierarchical video encoding device 2 and hierarchical video decoding device 1 can be used for transmission and reception of video. FIG. 22A is a block diagram illustrating a configuration of a transmission device PROD_A in which the hierarchical video encoding device 2 is mounted.

  As illustrated in FIG. 22A, the transmission device PROD_A modulates a carrier wave with an encoding unit PROD_A1 that obtains encoded data by encoding a moving image and the encoded data obtained by the encoding unit PROD_A1. Thus, a modulation unit PROD_A2 that obtains a modulation signal and a transmission unit PROD_A3 that transmits the modulation signal obtained by the modulation unit PROD_A2 are provided. The hierarchical moving image encoding apparatus 2 described above is used as the encoding unit PROD_A1.

  The transmission device PROD_A is a camera PROD_A4 that captures a moving image, a recording medium PROD_A5 that records the moving image, an input terminal PROD_A6 that inputs the moving image from the outside, as a supply source of the moving image input to the encoding unit PROD_A1. An image processing unit A7 that generates or processes an image may be further provided. In FIG. 22A, the configuration in which the transmission apparatus PROD_A includes all of these is illustrated, but a part thereof may be omitted.

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

  FIG. 22B is a block diagram illustrating a configuration of a receiving device PROD_B in which the hierarchical video decoding device 1 is mounted. As illustrated in FIG. 22B, the reception device PROD_B includes a reception unit PROD_B1 that receives a modulated signal, a demodulation unit PROD_B2 that obtains encoded data by demodulating the modulation signal received by the reception unit PROD_B1, and a demodulation A decoding unit PROD_B3 that obtains a moving image by decoding the encoded data obtained by the unit PROD_B2. The above-described hierarchical video decoding device 1 is used as the decoding unit PROD_B3.

  The receiving device PROD_B has a display PROD_B4 for displaying a moving image, a recording medium PROD_B5 for recording the moving image, and an output terminal for outputting the moving image to the outside as a supply destination of the moving image output by the decoding unit PROD_B3. PROD_B6 may be further provided. FIG. 22B illustrates a configuration in which the reception apparatus PROD_B includes all of these, but a part of the configuration may be omitted.

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

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

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

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

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

  Based on FIG. 23, it will be described that the above-described hierarchical video encoding device 2 and hierarchical video decoding device 1 can be used for recording and reproduction of video. FIG. 23A is a block diagram illustrating a configuration of a recording apparatus PROD_C in which the above-described hierarchical video encoding apparatus 2 is mounted.

  As shown in (a) of FIG. 23, the recording device PROD_C includes an encoding unit PROD_C1 that obtains encoded data by encoding a moving image, and the encoded data obtained by the encoding unit PROD_C1 on the recording medium PROD_M. A writing unit PROD_C2 for writing. The hierarchical moving image encoding device 2 described above is used as the encoding unit PROD_C1.

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

  The recording device PROD_C is a camera PROD_C3 that captures moving images as a supply source of moving images to be input to the encoding unit PROD_C1, an input terminal PROD_C4 for inputting moving images from the outside, and reception for receiving moving images. The unit PROD_C5 and an image processing unit C6 that generates or processes an image may be further provided. FIG. 23A illustrates a configuration in which the recording apparatus PROD_C includes all of these, but a part of the configuration may be omitted.

  The receiving unit PROD_C5 may receive a non-encoded moving image, or may receive encoded data encoded by a transmission encoding scheme different from the recording encoding scheme. You may do. In the latter case, a transmission decoding unit (not shown) that decodes encoded data encoded by the transmission encoding method may be interposed between the reception unit PROD_C5 and the encoding unit PROD_C1.

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

  FIG. 23B is a block diagram illustrating a configuration of a playback device PROD_D in which the above-described hierarchical video decoding device 1 is mounted. As shown in (b) of FIG. 23, the playback device PROD_D reads a moving image by decoding a read unit PROD_D1 that reads encoded data written to the recording medium PROD_M and a coded data read by the read unit PROD_D1. And a decoding unit PROD_D2 to be obtained. The hierarchical moving image decoding apparatus 1 described above is used as the decoding unit PROD_D2.

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

  In addition, the playback device PROD_D has a display PROD_D3 that displays a moving image, an output terminal PROD_D4 that outputs the moving image to the outside, and a transmission unit that transmits the moving image as a supply destination of the moving image output by the decoding unit PROD_D2. PROD_D5 may be further provided. FIG. 23B illustrates a configuration in which the playback apparatus PROD_D includes all of these, but a part of the configuration may be omitted.

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

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

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

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

  Examples of the recording medium include tapes such as magnetic tapes and cassette tapes, magnetic disks such as floppy (registered trademark) disks / hard disks, CD-ROM (Compact Disc Read-Only Memory) / MO (Magneto-Optical) / Disks including optical disks such as MD (Mini Disc) / DVD (Digital Versatile Disk) / CD-R (CD Recordable), cards such as IC cards (including memory cards) / optical cards, mask ROM / EPROM (Erasable Programmable Read-only Memory (EEPROM) (Electrically Erasable and Programmable Read-only Memory) / Semiconductor memories such as flash ROM, or logic circuits such as PLD (Programmable Logic Device) and FPGA (Field Programmable Gate Array) Etc. can be used.

  Further, each of the above devices may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited as long as it can transmit the program code. For example, the Internet, an intranet, an extranet, a LAN (Local Area Network), an ISDN (Integrated Services Digital Network), a VAN (Value-Added Network), a CATV (Community Antenna Television) communication network, a virtual private network (Virtual Private Network), A telephone line network, a mobile communication network, a satellite communication network, etc. can be used. The transmission medium constituting the communication network may be any medium that can transmit the program code, and is not limited to a specific configuration or type. For example, infra-red such as IrDA (Infrared Data Association) or remote control, such as IEEE (Institute of Electrical and Electronic Engineers) 1394, USB, power line carrier, cable TV line, telephone line, ADSL (Asymmetric Digital Subscriber Line) line, etc. , Bluetooth (registered trademark), IEEE 802.11 wireless, HDR (High Data Rate), NFC (Near Field Communication), DLNA (Digital Living Network Alliance), mobile phone network, satellite line, terrestrial digital network, etc. Is possible. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

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

1. Hierarchical video decoding device (image decoding device)
DESCRIPTION OF SYMBOLS 11 NAL demultiplexing part 12 Parameter set decoding part 13 Tile setting part 14 Slice decoding part 141 Slice header decoding part 142 Slice position setting part 143, 243 Skip slice determination part 144 CTU decoding part 144N Non-skip CTU decoding part 144S Skip CTU generation 15 Base decoding unit 16 Decoded picture management unit 2 Hierarchical video encoding device (image encoding device)
21 NAL multiplexing unit 22 Parameter set encoding unit 23 Tile setting unit 24 Slice encoding unit 241 Slice header setting unit 242 Slice position setting unit 244 CTU encoding unit 244N Non-skip CTU encoding unit 244S Skip CTU encoding unit 3 layers Coded data converter 32 Parameter set correction unit 34 Slice correction unit SYS Attention area display system SYS1A, SYS1B Hierarchical moving image encoding unit SYS2 Hierarchical encoded data storage unit SYS3 Hierarchical encoded data conversion unit SYS4 Hierarchical moving image decoding unit SYS5 Display Control unit SYS6 ROI display unit (attention area display unit)
SYS7 Overall display section SYS8 ROI notification section (attention area notification section)

Claims (16)

An image decoding apparatus that decodes higher layer encoded data included in hierarchically encoded data and restores a decoded picture of an upper layer,
A slice header decoding unit for decoding the slice header of the upper layer;
A non-skip CTU decoding unit that decodes a decoded image of a CTU belonging to a non-skip slice of an upper layer based on slice data;
A skip CTU generation unit that generates a decoded image of a CTU belonging to a skip slice of an upper layer;
The slice header decoding unit decodes or estimates a skip slice flag indicating whether the target slice is a skip slice or a non-skip slice,
When the skip slice flag indicates that the target slice is a skip slice, the slice header decoding unit decodes the number of skip CTUs that is the number of CTUs included in the target slice, and the number of skip CTUs indicates the number of skip CTUs. A decoded image of the target slice is generated by generating a decoded image of the CTU by the skip CTU generation unit,
When the skip slice flag indicates that the target slice is a non-skip slice, a decoded image of the target slice is generated by decoding the CTU included in the target slice by the non-skip CTU decoding unit. Image decoding device. A parameter set decoding unit for decoding display area information;
The display area specified by the display area information does not include a tile including a skip slice, but includes a tile, and all the slices included in the tile are non-skip slices. The image decoding device according to 1.   The skip CTU number is decoded from a slice header by applying a decoding process of a variable length code having a maximum value of the number of CTUs included in a tile to which the target slice belongs. Image decoding apparatus.   When the picture including the target slice includes one tile, the skip slice flag decoded or estimated by the slice header decoding unit indicates that the target slice is a non-skip slice. The image decoding device according to claim 3. A parameter set decoding unit for decoding all tile-dependent identifiers included in the parameter set;
The skip slice flag decoded or estimated by the slice header decoding unit when the all-tile dependency identifier indicates that there is no motion dependency other than between corresponding tiles or no inter-layer dependency other than between corresponding tiles. The image decoding apparatus according to claim 1, wherein indicates that the target slice is a non-skip slice. When the picture including the target slice includes two or more tiles, the slice header decoding unit decodes the skip slice flag,
The slice header decoding unit estimates a value indicating that the target slice is a non-skip slice as a value of the skip slice flag when a picture including the target slice includes one tile. 5. The image decoding device according to 4. When the picture including the target slice includes two or more tiles, the slice header decoding unit selects either the non-skip CTU decoding unit or the skip CTU generation unit according to the value of the skip slice flag. To decode the CTU contained in the target slice,
The slice header decoding unit selects a non-skip CTU decoding unit to decode a CTU included in the target slice when a picture including the target slice includes one tile. Image decoding device.   6. The all-tile dependency identifier includes both information indicating presence / absence of motion dependence other than between corresponding tiles and information indicating presence / absence of inter-layer dependence other than between corresponding tiles. Image decoding device. A parameter set decoding unit for decoding all tile-dependent identifiers included in the parameter set;
The picture including the target slice includes two or more tiles, and the all-tile dependency identifier indicates that there is no motion dependency other than between corresponding tiles or no inter-layer dependency other than between corresponding tiles. 4. The image decoding device according to claim 1, wherein the skip slice flag decoded or estimated by the slice header decoding unit indicates that the target slice is a non-skip slice. An image encoding device that generates encoded data of an upper layer from an input image,
A slice header encoding unit that encodes a slice header of an upper layer;
A non-skip CTU encoding unit that encodes a decoded image of a CTU belonging to a non-skip slice of an upper layer based on slice data;
A skip CTU generation unit that generates a decoded image of a CTU belonging to a skip slice of an upper layer;
A parameter set encoder for encoding display area information;
The slice header encoding unit encodes a skip slice flag indicating whether the target slice is a skip slice or a non-skip slice,
When the skip slice flag indicates that the target slice is a skip slice, the slice header encoding unit encodes the number of skip CTUs that is the number of CTUs included in the target slice and indicates the number of skip CTUs. A decoded image of the target slice is generated by generating a decoded image of the number of CTUs by the skip CTU generation unit,
When the skip slice flag indicates that the target slice is a non-skip slice, the decoded image of the target slice is generated by generating the CTU included in the target slice by the non-skip CTU encoding unit,
The display area specified by the display area information does not include a tile including a skip slice, but includes a tile, and all the slices included in the tile include a non-skip slice. apparatus. A hierarchical encoded data conversion device that converts input hierarchical encoded data based on input attention area information and outputs the converted hierarchical encoded data,
A slice correction unit for correcting the encoded data of the upper layer based on the attention area information,
The slice correction unit is configured to change a slice that is included in the encoded data of the upper layer and is not included in the attention area from a non-skip slice to a skip slice based on the attention area indicated by the attention area information. 1. A hierarchical encoded data conversion apparatus for correcting encoded data of an upper layer in   The slice correction unit is a slice included in the encoded data of the upper layer, and the encoded data of the upper layer is changed by changing a slice included in the tile not included in the attention area from a non-skip slice to a skip slice. The hierarchical encoded data conversion apparatus according to claim 11, wherein: It has a parameter set correction unit,
The parameter set correction unit corrects the parameter set by rewriting the display area information included in the parameter set so that the display area indicated by the display area information matches the attention area indicated by the attention area information. The hierarchical encoded data conversion device according to claim 11 or 12. An attention area display system that displays an entire picture and a partial area corresponding to the attention area of the picture using the accumulated hierarchical encoded data,
An attention area notification unit for supplying attention area information;
A hierarchically encoded data converter that converts hierarchically encoded data based on the attention area information to generate converted hierarchically encoded data; and
A hierarchical moving picture decoding unit that decodes the transformed hierarchically encoded data and outputs a decoded picture of an upper layer and a decoded picture of a lower layer;
An attention area display system comprising: a display control unit that outputs the decoded picture of the lower layer as a whole display image and outputs the decoded picture of the upper layer as an attention area display image.   The attention area display system according to claim 14, wherein the display control section does not output an attention area display image when the attention area information indicates that an attention area is not designated. When there is a change in attention area information, the display control section starts from the time when the change is determined until the decoded picture of the upper layer related to the attention area information after the change is supplied from the hierarchical video decoding section. The attention area according to claim 14 or 15, characterized in that a partial area of the decoded picture of the lower layer and indicated by the changed attention area information is output as an attention area display image. Area display system.