JP2013118424A - Image decoding device, image encoding device, and data structure of encoded data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize efficient encoding/decoding processing utilizing properties of PU partition types belonging to the same PU partition type group.SOLUTION: A moving image decoding device 1 comprises a variable table adaptation unit 1015 that, when a rectangular PU partition type belonging to a PU group has been restored with respect to a target CU, performs adaptive processing so that a code shorter than before decoding is decoded for each rectangular PU partition type belonging to the PU group.

Description

  The present invention relates to an image decoding device that decodes encoded data representing an image, an image encoding device that generates encoded data by encoding an image, and moving image encoded data received therebetween. Regarding data structure.

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

  As a specific moving picture encoding method, for example, H.264 is used. H.264 / MPEG-4. A method used in KTA software, which is a codec for joint development in AVC and VCEG (Video Coding Expert Group), a method used in TMuC (Test Model under Consideration) software, and a successor codec, HEVC (High- Efficiency Video Coding) (Non-Patent Document 1) and the like can be mentioned.

  In such a moving image coding system, an image (picture) constituting a moving image is a slice obtained by dividing the image, a coding unit (Coding Unit) obtained by dividing the slice. And is managed by a hierarchical structure composed of blocks and partitions obtained by dividing an encoding unit, and is normally encoded / decoded block by block.

  In such a moving image coding method, a predicted image is usually generated based on a local decoded image obtained by encoding / decoding an input image, and the predicted image is generated from the input image (original image). A prediction residual obtained by subtraction (sometimes referred to as “difference image” or “residual image”) is encoded. 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, based on a locally decoded image in the same frame, predicted images in the frame are sequentially generated.

  On the other hand, in inter prediction, by applying motion compensation using a motion vector to a reference image in a reference frame (decoded image) obtained by decoding the entire frame, a predicted image in a prediction target frame is converted into a prediction unit ( For example, it is generated for each block).

  For inter prediction, a technique (AMP; Asymmetric Motion Partition) that divides a coding unit, which is a unit of coding processing, into an asymmetric partition (PU) has been proposed (Non-Patent Document 1).

  In AMP, a plurality of rectangular PU partition types in the horizontal direction and the vertical direction are defined. Specifically, there are three types of PU division types of 2N × N, 2N × nU, and 2N × nD in the rectangular PU in the horizontal direction. In addition, there are three types of PU division types of N × 2N, nL × 2N, and nR × 2N in the vertical rectangular PU.

  The PU partition type is decoded / encoded as a syntax cu_split_pred_part_mode combined with information on a CU partition flag, a skip flag, a merge flag, and a CU prediction mode. 37 and 38 show a definition table of syntax values of cu_split_pred_part_mode. FIG. 37 shows the definition table J101 when CUWidth (CU width)> 8, and FIG. 38 shows the definition table J102 when CUWidth (CU width) = 8.

  In the encoding process, each syntax value is encoded by an entropy encoding method.

  As entropy coding methods, context adaptive variable length coding (CALVC) and context adaptive binary arithmetic coding (CABAC) are known. ing.

  Here, CAVLC will be described in more detail as follows. In encoding by the VLC (Variable Length Coding) method, code number conversion information indicating a correspondence between a syntax value and a code number (codeNum), and bit conversion indicating a correspondence between a code number and a bit string Information is used. Such information is expressed in the form of a table, expressed by a calculation formula for deriving parameters (for example, a calculation formula for obtaining a code number from a syntax value), or A combination may be used. In encoding by CAVLC, such conversion processing is adaptively performed based on context (Context-based Adaptive).

  Specifically, encoding by CAVLC is performed according to the following procedure. First, using the code number conversion information, the syntax value is converted into a code number. Next, the code number is converted into a bit string using the bit conversion information.

  In encoding, one of a plurality of VLC methods is adaptively selected and encoded according to the context.

  Here, the context refers to the status (context) of encoding / decoding, and refers to past encoding / decoding results of the related syntax. Examples of the related syntax include various syntaxes related to intra prediction and inter prediction, various syntaxes related to luminance (Luma) and chrominance (Chroma), and various syntaxes related to CU (Coding Unit coding unit) size.

  Further, Non-Patent Document 1 proposes a technique for reducing the amount of code for CAVLC by adaptively switching the code number associated with each PU partition type using a variable table. Specifically, it is as follows.

  First, the code number corresponding to cu_split_pred_part_mode is encoded / decoded using a truncated unary code. Therefore, a short code is assigned to a small code number.

  The above-described adaptation of the variable table is realized by adjusting the elements of the variable table so that the syntax value (PU partition type) to be decoded / encoded is associated with a smaller code number. Therefore, a smaller code number is assigned to the most recently generated syntax value. Therefore, a shorter code is assigned to the most recently generated syntax value.

  Because of the local nature of the image, the same syntax value (same PU partition type) is likely to occur continuously, so the code amount can be determined by assigning a shorter code to the most recently generated syntax value. Can be reduced.

`` WD4: Working Draft 4 of High-Efficiency Video Coding (JCTVC-F803_d1) '', Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO / IEC JTC1 / SC29 / WG11 6th Meeting: Torino, IT, 14-22 July, 2011 (released September 8, 2011)

  As described above, there are a plurality of PU division types including rectangular PUs in the same direction (three types each for vertical and horizontal). Moreover, when any PU partition type is selected from among PU partition types including rectangular PUs in the same direction, other PU partition types belonging to the same group are likely to occur. However, in the current adaptation of the variable table, such a property is not fully considered.

  The present invention has been made in view of the above problems, and an object of the present invention is to realize an efficient encoding / decoding process utilizing the properties of PU partition types belonging to the same PU partition type group. A decoding device, an image encoding device, and a data structure of encoded data are provided.

  In order to solve the above-described problem, the image decoding apparatus according to the present invention generates a prediction image for each prediction unit obtained by dividing a coding unit into a number of one or more according to a predetermined prediction unit division type. In the image decoding apparatus that restores, there are a plurality of rectangular prediction unit division types that are prediction unit division types into rectangular prediction units as the predetermined prediction unit division type, and two or more rectangular prediction unit division types belong to When the rectangular prediction unit division type belonging to the prediction unit division type group is restored for the coding unit to be processed, the rectangular prediction belonging to the prediction unit division type group is defined. Each unit division type is characterized by comprising adaptive processing means for performing adaptive processing so that codes shorter than before decoding are decoded.

  The image decoding apparatus obtains a prediction unit by dividing a coding unit into one or more numbers according to a predetermined prediction unit division type.

  As specific, specific prediction unit partition types, for example, PU partition types are 2N × 2N, 2N × N, 2N × nU, 2N × nD, N × 2N, nL × 2N, nR × 2N, and N × N and the like.

  Furthermore, in the example of the prediction unit division type, the prediction unit division types into rectangular prediction units are 2N × N, 2N × nU, 2N × nD, N × 2N, nL × 2N, and nR × 2N. . These prediction unit division types include 2N × N, 2N × nU, and 2N × nD, which are prediction unit division types into horizontally long rectangular prediction units, and N × 2N, which is a prediction unit division type into vertically long rectangular prediction units. , NL × 2N, and nR × 2N.

  The prediction unit division type group is a group to which two or more rectangular prediction unit division types belong. In the above example, for example, 2N × N, 2N × nU, and 2N × nD, which are prediction unit division types into horizontally long rectangular prediction units, can be made into one group. Moreover, it is also possible to make all the prediction unit division | segmentation types into the rectangular prediction unit mentioned above into one group.

  By the way, there are situations in which some related prediction unit division types that have the same division direction occur continuously. For example, in an area where there is an edge close to horizontal, the occurrence probability of each prediction unit division type including a horizontally long prediction unit tends to increase.

  According to the above configuration, when the rectangular prediction unit division type belonging to the prediction unit division type group is restored for the encoding unit to be processed, for each rectangular prediction unit division type belonging to the prediction unit division type group Then, adaptive processing is performed so that codes shorter than before decoding are decoded.

  Thereby, in the above situations, the code amount can be reduced by assigning a short code to the rectangular prediction unit division types belonging to the same prediction unit division type group.

  In the image decoding device according to the present invention, the prediction unit partition type group is defined as a union of a set of prediction unit partition types into horizontally long rectangular prediction units and a set of prediction unit partition types into vertically long rectangular prediction units. It is preferable.

  In an area where the texture is complex, there is a property that non-square prediction unit division types occur continuously.

  According to the above configuration, the prediction unit division type group includes both a prediction unit division type group into horizontally long rectangular prediction units and a prediction unit division type group into vertically long rectangular prediction units. For this reason, in such an area where the texture is complex, a short code can be decoded for a non-square prediction unit division type included in the prediction unit division type group. As a result, the code amount can be reduced.

  In the image decoding apparatus according to the present invention, the prediction unit division type group is defined as a set of prediction unit division types into horizontally long rectangular prediction units or a set of prediction unit division types into vertically long rectangular prediction units. Is preferred.

  According to the above configuration, the prediction unit division type group is a prediction unit division type group into horizontally long rectangular prediction units or a prediction unit division type group into vertically long rectangular prediction units. In a situation where a horizontally long rectangular prediction unit or a vertically long rectangular prediction unit is continuously generated, the code amount can be reduced.

  For example, in a situation where horizontal rectangular prediction units are generated continuously, a short code can be decoded for the horizontal rectangular prediction unit division type, so that the amount of codes can be reduced.

  In the image decoding apparatus according to the present invention, the decoding means for decoding the code number from each code included in the encoded data, the prediction unit division type group, and the code number corresponding to the prediction unit division type group are associated with each other. A prediction unit division type group obtaining unit that obtains a prediction unit division type group corresponding to the code number decoded from the encoded data with reference to the variable table including the adaptive process by the adaptive processing unit It is preferable that the variable table adaptation process updates the variable table so that a smaller code number is associated with the prediction unit division type group.

  According to the above configuration, so-called variable table adaptation processing is performed. That is, in the encoded data, a code number corresponding to each syntax is encoded, and the code number and the prediction unit division type group are associated in the variable table. The shorter code number is assigned a shorter code.

  In addition, when the code number associated with the prediction unit partition type group is decoded, the variable table is updated by the variable table adaptation process so that a short code is decoded for the prediction unit partition type group. The

  The variable table adaptation processing includes, for example, a prediction unit division type group associated with a decoded code number and a prediction unit division type group associated with a code number that is 1 smaller than the decoded code number. Is a process of exchanging.

  In the variable table, a prediction unit partition type that does not belong to the prediction unit partition type group, such as inter 2N × 2N, may be associated with the code number. Further, such a prediction unit division type may be a target of the replacement process.

  Further, the variable table may be provided with a counter that counts the number of occurrences of a predetermined code number, and the variable table adaptation process may be performed when the value of the counter becomes equal to or greater than a predetermined value.

  By adopting such a variable table adaptive process, for example, an adaptive process in decoding by the CAVLC encoding method can be realized.

  In the image decoding apparatus according to the present invention, an addition for specifying which prediction unit division type is a rectangular prediction unit division type belonging to the prediction unit division type group acquired by the prediction unit division type group acquisition unit. It is preferable to provide additional information restoring means for restoring information.

  According to the above configuration, when the prediction unit division type belongs to the prediction unit division type group, the prediction unit division type further specifies which rectangular prediction unit division type belongs to the prediction unit division type group. Additional information can be restored and the final prediction unit partition type can be identified.

  In the image decoding apparatus according to the present invention, the prediction unit partition type group includes a prediction unit partition type of a symmetric partition and a prediction unit partition type of an asymmetric partition. On the other hand, it is preferable that a shorter code is assigned as compared with the prediction unit division type of the asymmetric partition.

  In a natural image, the prediction unit division type of a symmetric partition tends to have a higher probability of occurrence than the prediction unit division type of an asymmetric partition.

  According to the above configuration, the additional information is assigned with a shorter code than the prediction unit division type of the asymmetric partition, with respect to the prediction unit division type of the symmetric partition having a high occurrence probability, so that the code amount is reduced. There is an effect that can be.

  The image decoding apparatus according to the present invention includes arithmetic decoding means for arithmetically decoding a binary value indicating whether or not a prediction unit division type in a coding unit to be processed is included in the prediction unit division type group, The adaptive processing by the adaptive processing means is preferably processing for updating a probability table used in the arithmetic decoding of the binary value.

  The probability table is an index indicating the probability of occurrence of a binary value (0 or 1) used for arithmetic coding called a state in the CABAC coding method, for example. In the above configuration, an independent probability table is set to a binary value indicating whether or not the prediction unit division type in the coding unit to be processed is included in the prediction unit division type group.

  In the adaptive processing, by updating the probability table used in the arithmetic decoding of the binary value, a short code can be decoded for the binary value having a high occurrence probability.

  By adopting such an adaptive process, for example, an adaptive process in decoding by the CABAC encoding method can be realized.

  In the image decoding apparatus according to the present invention, the prediction unit division type group in which the prediction unit division type in the encoding unit to be processed is defined as a set of prediction unit division types into horizontally long rectangular prediction units, and the vertically long Arithmetic decoding means for arithmetically decoding binary values indicating which of the prediction unit division types defined as a set of prediction unit division types into rectangular prediction units is included, and the adaptive processing by the adaptive processing means Is preferably a process of updating a probability table used in the arithmetic decoding of the binary value.

  According to the above configuration, the prediction unit division type group in which the prediction unit division type in the encoding unit to be processed is defined as a set of prediction unit division types into horizontally long rectangular prediction units, and the vertically long rectangular prediction unit An independent probability table is set to a binary value indicating which of the above-mentioned prediction unit division types is defined as a set of prediction unit division types.

  Also by adopting the above configuration, it is possible to realize adaptive processing in decoding by the CABAC encoding method.

  In order to solve the above-described problem, an image encoding device according to the present invention generates an image for each prediction unit obtained by dividing an encoding unit into one or more numbers by a predetermined prediction unit division type. In the encoding apparatus, as the predetermined prediction unit division type, there are a plurality of rectangular prediction unit division types that are prediction unit division types into rectangular prediction units, and predictions to which two or more rectangular prediction unit division types belong. When a unit partition type group is defined and a rectangular prediction unit partition type belonging to the prediction unit partition type group occurs for the coding unit to be processed, a rectangular prediction unit partition type belonging to the prediction unit partition type group It is characterized by comprising an adaptive processing means for adaptively processing so that a shorter code than before generation is assigned to each.

  In order to solve the above-described problem, the data structure of the encoded data according to the present invention is a division scheme that divides the encoding unit into one or more numbers in order to obtain a prediction unit for generating a prediction image. In an image decoding apparatus that decodes the encoded data in a data structure of encoded data including prediction unit division information for specifying a predetermined prediction unit division type, a rectangular prediction unit is used as the predetermined prediction unit division type. There are a plurality of rectangular prediction unit division types that are prediction unit division types, and a prediction unit division type group to which two or more rectangular prediction unit division types belong is defined, and the encoded data is encoded Including additional information for identifying which rectangular prediction unit partition type belongs to the above prediction unit partition type group. It is characterized in.

  Note that an image encoding device having a configuration corresponding to the image decoding device and a data structure of encoded data transmitted / received between these devices also fall within the scope of the present invention. According to the image encoding device and the data structure of the encoded data configured as described above, the same effects as those of the image decoding device according to the present invention can be obtained.

  In order to solve the above-described problem, in the image decoding apparatus according to the present invention, a prediction image is generated for each prediction unit obtained by dividing a coding unit into a number of one or more according to a predetermined prediction unit division type. In the image decoding apparatus that restores, there are a plurality of types of rectangular prediction unit division types that are prediction unit division types into rectangular prediction units as the predetermined prediction unit division type, and at least some of the possible values are predicted. A syntax that is a value used for specifying a unit division type, and at least one value used for specifying the prediction unit division type is associated with a prediction unit division type group including two or more rectangular prediction unit division types. When the syntax decoding means for decoding the syntax that is the determined value and the prediction unit partition type included in the prediction unit partition type group are decoded , So that the smaller code number is assigned to the prediction unit division type group comprises adaptive processing means for updating the variable table used in the decoding of the syntax.

  The rectangular prediction unit is a prediction unit of a vertically long rectangle or a horizontally long rectangle having a size of 16 × 8 pixels, 8 × 16 pixels, 32 × 8 pixels, 8 × 32 pixels, or the like, and has a size of 16 × 16 pixels or 32 × 32 pixels. Does not include the square prediction unit.

  According to the above configuration, when a value corresponding to a prediction unit division type group including two or more of the rectangular prediction units is restored as the syntax value for the encoding unit to be processed, the syntax value is more than that before decoding. The variable table is updated so that a smaller code number is assigned.

  Since a short code is generally assigned to a small code number, a shorter code is assigned to the syntax value by the update process. Therefore, a shorter code is assigned to the prediction unit division type group including two or more rectangular prediction units by the update process.

  In a natural image, when a coding unit of the same size is used in a region where the image is complex, a non-square rectangular prediction unit tends to be generated regardless of the type. Therefore, when a certain rectangular prediction unit occurs, the probability of occurrence of other rectangular prediction units including the rectangular prediction unit increases. That is, there is a high possibility that continuously generated rectangular prediction units belong to the same rectangular prediction unit division type group. Therefore, syntax values corresponding to the same rectangular prediction unit division type group are easily generated continuously. Therefore, when a rectangular prediction unit division type group is generated by the update process, a short code can be assigned to the rectangular prediction unit division type group, so that the code amount can be reduced.

  In the image decoding apparatus according to the present invention, the syntax is a combined syntax of at least one of coding unit partition information, skip flag, merge flag, and CU prediction scheme information, and prediction unit partition type information. Is preferred.

  According to the above configuration, in the configuration in which at least a part of the coding unit division information, the skip flag, the merge flag, and the CU prediction scheme information is decoded together with the prediction unit division type information for each coding unit, adaptive processing is performed. realizable.

  In the image decoding apparatus according to the present invention, the syntax is preferably a combined syntax of coding unit division information, skip flag, CU prediction method information, and prediction unit division type.

  According to the above configuration, adaptive processing can be realized in the configuration in which the coding unit division information, the skip flag, the CU prediction scheme information, and the prediction unit division type are decoded together with the prediction unit division type information.

  In the image decoding apparatus according to the present invention, it is preferable that the syntax is a combined syntax of a skip flag, a merge flag, CU prediction method information, and a prediction unit division type.

  According to the above configuration, the adaptive processing can be realized in the configuration in which the skip flag, the merge flag, the CU prediction scheme information, and the prediction unit partition type are decoded together with the prediction unit partition type information.

  In the image decoding apparatus according to the present invention, the prediction unit partition type group includes a symmetric rectangular prediction unit partition type group that is a set of prediction unit partition types of a symmetric partition including a rectangular prediction unit, and a rectangular prediction unit. An asymmetric rectangular prediction unit partitioning type group that is a set of prediction unit partitioning types of asymmetric partitions is defined at least, and the first value that the syntax can take is associated with the symmetric rectangular prediction unit partitioning type group. It is preferable that the second value that can be taken by the syntax is a value associated with the asymmetric rectangular prediction unit division type group.

  According to the above configuration, different syntax values are associated with the symmetric rectangular prediction unit division type group and the asymmetric rectangular prediction unit division type group. Further, when each prediction unit division type group is decoded, an adaptive process is performed so that a short code is assigned with a corresponding syntax value.

  In general, a symmetric partition tends to occur more easily than an asymmetric partition, and in an area where rectangular prediction units occur continuously, an area where only the rectangular prediction units of the symmetric partition occur continuously and a symmetric partition. Regardless of the asymmetric partition, there is an area where rectangular prediction units occur continuously. By assigning different syntax values to the symmetric rectangular prediction unit group and the asymmetric rectangular prediction unit group, in the former case, a shorter code can be assigned to the symmetric rectangular prediction unit, so that the code amount can be reduced.

  In the image decoding apparatus according to the present invention, the prediction unit division type group includes an intra rectangular prediction unit division type group including a rectangular prediction unit in an intra coding unit, and a rectangular prediction unit in an inter coding unit. An inter-rectangular prediction unit division type group is defined at least, and a first value that can be taken by the syntax is a value associated with the intra-rectangular prediction unit division type group, and a second value that can be taken by the syntax. Is a value associated with the inter-rectangular prediction unit division type group.

  According to the above configuration, different syntax values are assigned to the inter rectangular prediction unit division type group and the intra rectangular prediction unit division type group. Further, when each prediction unit division type group is decoded, an adaptive process is performed so that a short code is assigned with a corresponding syntax value.

  In general, the intra-rectangular prediction unit division type group tends to be easily selected in a complicated area as compared to the inter-rectangular prediction unit division type group. According to said structure, when an intra rectangular prediction unit division | segmentation type group generate | occur | produces continuously in the area | region where complexity is high, a short code | symbol is assigned with respect to the prediction unit division | segmentation type group. Also, even when inter-rectangular prediction unit division type groups occur continuously in other regions, a short code is assigned to the same prediction unit division type group, so that the amount of codes can be reduced.

  In order to solve the above problems, in the image coding apparatus according to the present invention, an image that generates a prediction image for each prediction unit obtained by dividing a coding unit into one or more numbers by a predetermined prediction unit division type. In the encoding apparatus, as the predetermined prediction unit division type, there are a plurality of types of rectangular prediction unit division types that are prediction unit division types into rectangular prediction units, and at least a part of possible values is a prediction unit division type. Is a syntax that is a value used for specifying the prediction unit, and at least one of the values used for specifying the prediction unit partition type is a value associated with a prediction unit partition type group including two or more rectangular prediction unit partition types When the syntax encoding means for encoding the syntax and the prediction unit partition type included in the prediction unit partition type group occur, As assigned a smaller code numbers for measuring unit division type group comprises adaptive processing means for updating the variable table used in the decoding of the syntax.

  An image encoding device having a configuration corresponding to the image decoding device also falls within the scope of the present invention. According to the image encoding device configured as described above, it is possible to achieve the same effects as the image decoding device according to the present invention.

  An image decoding apparatus according to the present invention is an image decoding apparatus that generates a prediction image and restores an image for each prediction unit obtained by dividing a coding unit into a number of one or more according to a predetermined prediction unit division type. As the predetermined prediction unit division type, there are a plurality of rectangular prediction unit division types that are prediction unit division types into rectangular prediction units, and the prediction unit division type group to which two or more rectangular prediction unit division types belong is defined. When the rectangular prediction unit division type belonging to the prediction unit division type group is restored for the encoding unit to be processed, decoding is performed for each rectangular prediction unit division type belonging to the prediction unit division type group. It is a structure provided with the adaptive process means which performs an adaptive process so that a code shorter than before may be decoded.

  The image coding apparatus according to the present invention is an image coding apparatus that generates a predicted image for each prediction unit obtained by dividing a coding unit into a number of one or more according to a predetermined prediction unit division type. As the unit division type, there are multiple types of rectangular prediction unit division types that are prediction unit division types into rectangular prediction units, and the prediction unit division type group to which two or more of the above rectangular prediction unit division types belong is defined. When a rectangular prediction unit division type belonging to the prediction unit division type group occurs for the encoding unit to be processed, for each rectangular prediction unit division type belonging to the prediction unit division type group, This is a configuration provided with adaptive processing means for performing adaptive processing so that a short code is assigned.

  The data structure of the encoded data according to the present invention specifies a predetermined prediction unit division type, which is a division method for dividing an encoding unit into one or more numbers, in order to obtain a prediction unit for generating a prediction image. In the data structure of the encoded data including the prediction unit division information for decoding, in the image decoding apparatus for decoding the encoded data, the predetermined prediction unit division type is a rectangle that is a prediction unit division type into a rectangular prediction unit There are a plurality of prediction unit partition types, a prediction unit partition type group to which two or more of the rectangular prediction unit partition types belong is defined, and the encoded prediction unit partition type is the above It is a data structure including additional information for specifying which rectangular prediction unit division type belongs to the prediction unit division type group.

  In the image decoding apparatus according to the present invention, in the image decoding apparatus that generates a prediction image and restores an image for each prediction unit obtained by dividing a coding unit into a number of one or more according to a predetermined prediction unit division type, As the predetermined prediction unit division type, there are a plurality of rectangular prediction unit division types that are prediction unit division types into rectangular prediction units, and at least some of the possible values are values used for specifying the prediction unit division type. Decoding a syntax having a certain syntax and at least one value used for specifying the prediction unit partition type is a value associated with a prediction unit partition type group including two or more rectangular prediction unit partition types And when the prediction unit division type included in the prediction unit division type group is decoded, the prediction unit division type group As assigned a smaller code number against comprises adaptive processing means for updating the variable table used in the decoding of the syntax.

  In the image encoding device according to the present invention, in the image encoding device that generates a prediction image for each prediction unit obtained by dividing a coding unit into one or more numbers by a predetermined prediction unit division type, the predetermined prediction is performed. As the unit division type, there are a plurality of types of rectangular prediction unit division types that are prediction unit division types into rectangular prediction units, and at least a part of the possible values is a syntax that is used to specify the prediction unit division type. And at least one of the values used for specifying the prediction unit partition type is a syntax for encoding a syntax that is a value associated with a prediction unit partition type group including two or more rectangular prediction unit partition types. When a tax encoding unit and a prediction unit division type included in the prediction unit division type group occur, Small code number Ri is assigned as comprises adaptive processing means for updating the variable table used in the decoding of the syntax.

  Therefore, in the situation as described above, the code amount can be reduced by assigning a short code to the rectangular prediction unit partition types belonging to the same prediction unit partition type group.

It is a functional block diagram shown about the structural example of the CU information decoding part with which the moving image decoding apparatus which concerns on one Embodiment of this invention is provided, and a decoding module. It is the functional block diagram shown about the schematic structure of the said moving image decoding apparatus. It is a figure which shows the data structure of the encoding data produced | generated by the moving image encoder which concerns on one Embodiment of this invention, and decoded by the said moving image decoder, (a)-(d) is a picture, respectively. It is a figure which shows a layer, a slice layer, a tree block layer, and a CU layer. It is a figure which shows the pattern of PU division | segmentation type. (A) to (h) are PU partition types of 2N × 2N, 2N × N, 2N × nU, 2N × nD, N × 2N, nL × 2N, nR × 2N, and N × N, respectively. The partition shape in case is shown. It is a figure shown about the outline of the CAVLC encoding / decoding process using a variable table. It is a figure which shows the structural example of PU division type definition table in the case of CUWidth> 8. It is a figure which shows the structural example of the PU division | segmentation residual information definition table in the case of CUWidth> 8. It is a figure which shows the specific structural example of PU size table in which the number and size of PU are defined in correlation with the size of CU and PU division | segmentation type. It is a figure explaining the variable table adaptation process which the variable table adaptation part with which the said moving image decoding apparatus is provided. It is the flowchart shown about the flow of the prediction mode determination process in the combination syntax determination part with which the said moving image decoding apparatus is provided. It is the flowchart shown about the flow of the prediction mode decoding process in the joint syntax decoding part with which the said moving image decoding apparatus is provided. It is a figure which shows the example of the condition where a different kind of horizontally long rectangular PU division | segmentation type generate | occur | produces continuously. It is a figure shown about another example of the condition where a different kind of horizontally long rectangular PU division | segmentation type generate | occur | produces continuously. It is a figure which shows the structural example of the syntax table of an encoding tree level. It is a figure which shows another structural example of the syntax table of an encoding tree level. It is a figure which shows another example of a structure of the syntax table of an encoding tree level. It is a figure which shows the structural example of the syntax definition table which matches the pair of pred_part_mode, PredMode, and PartMode. It is a figure which shows another example of a structure of the syntax table of an encoding tree level. It is a figure which shows the structural example of the syntax table of an encoding unit level. It is a figure which shows the example of 1 structure of the syntax definition table of pred_part_mode defined about the case where CU size is 16x16 or more (in the case of non-minimum CU). It is a figure which shows the example of 1 structure of the syntax definition table of pred_part_mode defined about the case where CU size is 8x8 (in the case of minimum CU). It is a figure which shows another example of a structure of the syntax table of an encoding tree level. It is a figure which shows another structural example of the definition table of the syntax defined about the case where CU size is 16x16 or more (in the case of non-minimum CU). It is a figure which shows one structural example of the joint syntax definition table defined about the case where CU size is 16x16 or more (in the case of non-minimum CU). It is a figure which shows the example of 1 structure of the combined syntax definition table defined about the case where CU size is 8x8 (in the case of minimum CU). It is a figure which shows the example of 1 structure of the syntax definition table defined about the case where CU size is 16x16 or more (in the case of non-minimum CU). It is a figure which shows one structural example of the binary setting system in the case of using CABAC. It is a figure which shows the example of 1 structure of a syntax definition table in the case of using an inter 2Nx2N flag. It is a figure which shows the structural example of the syntax table of an encoding unit level. It is a figure which shows the example of the variable table adaptation process at the time of assigning an independent syntax value with respect to each PU partition type which belongs to a horizontally long rectangular PU group, and each PU partition type which belongs to a vertically long rectangular PU group. It is a figure which shows one structural example of the binary string arithmetically encoded. It is a figure shown about a variable table with a number counter and a sum counter. It is a figure shown about a variable table with a difference value counter. It is the functional block diagram shown about the schematic structure of the moving image encoder which concerns on one Embodiment of this invention. It is the figure shown about the structure of the transmitter which mounts the said moving image encoder, and the receiver which mounts the said moving image decoder. (A) shows a transmitting apparatus equipped with a moving picture coding apparatus, and (b) shows a receiving apparatus equipped with a moving picture decoding apparatus. It is the figure shown about the structure of the recording device which mounts the said moving image encoder, and the reproducing | regenerating apparatus which mounts the said moving image decoder. (A) shows a recording apparatus equipped with a moving picture coding apparatus, and (b) shows a reproduction apparatus equipped with a moving picture decoding apparatus. FIG. 10 is a definition table of a binding syntax when CUWidth (CU width)> 8 in the prior art. It is a definition table of a join syntax when CUWidth (CU width) = 8 in the prior art. This is a definition table of a binding syntax (cu_split_pred_part_mode) that can be used in common when the CU size is 16 × 16 or more and when the CU size is 8 × 8. It is a table for variable table initialization applied when matching with the code number (codeNum) in a variable table and the syntax value of cu_split_pred_part_mode is implement | achieved. It is a figure which shows one structural example of the syntax definition table regarding cu_split_pred_part_mode defined about the case where CU size is 16x16 or more (in the case of non-minimum CU). It is a figure which shows one structural example of the syntax definition table regarding cu_split_pred_part_mode defined about the case where CU size is 8x8 (in the case of minimum CU). It is a figure which shows one structural example of the syntax definition table regarding cu_split_pred_part_mode defined about the case where CU size is 16x16 or more (in the case of non-minimum CU). It is a figure which shows one structural example of the syntax definition table regarding cu_split_pred_part_mode defined about the case where CU size is 8x8 (in the case of minimum CU). It is a figure which shows the structural example of the syntax table of an encoding unit level. It is a figure which shows one structural example of the syntax definition table regarding cupred_part_mode defined about the case where CU size is 16x16 or more (in the case of non-minimum CU). It is a figure which shows one structural example of the syntax definition table regarding cu_pred_part_mode defined about the case where CU size is 8x8 (in the case of minimum CU). It is a figure which shows one structural example of the syntax definition table regarding cu_split_pred_part_mode defined about the case where CU size is 16x16 or more (in the case of non-minimum CU). It is a figure which shows one structural example of the syntax definition table regarding cu_split_pred_part_mode defined about the case where CU size is 8x8 (in the case of minimum CU).

  An embodiment of the present invention will be described with reference to FIGS. First, an overview of the moving picture decoding apparatus (image decoding apparatus) 1 and the moving picture encoding apparatus (image encoding apparatus) 2 will be described with reference to FIG. FIG. 2 is a functional block diagram showing a schematic configuration of the moving picture decoding apparatus 1.

  The moving picture decoding apparatus 1 and the moving picture encoding apparatus 2 shown in FIG. 264 / MPEG-4 AVC standard technology, VCEG (Video Coding Expert Group) codec for joint development in KTA software, TMuC (Test Model under Consideration) software The technology and the technology proposed by HEVC (High-Efficiency Video Coding), which is the successor codec, are implemented.

  The video encoding device 2 generates encoded data # 1 by entropy encoding a syntax value defined to be transmitted from the encoder to the decoder in these video encoding schemes. .

  As entropy coding methods, context adaptive variable length coding (CAVLC) and context adaptive binary arithmetic coding (CABAC) are known. ing.

  In encoding / decoding by CAVLC and CABAC, processing adapted to the context is performed. The context is an encoding / decoding situation (context), and is determined by past encoding / decoding results of related syntax. Examples of the related syntax include various syntaxes related to intra prediction and inter prediction, various syntaxes related to luminance (Luma) and chrominance (Chroma), and various syntaxes related to CU (Coding Unit coding unit) size. In CABAC, the binary position to be encoded / decoded in binary data (binary string) corresponding to the syntax may be used as the context.

  In CAVLC, various syntaxes are encoded by adaptively changing the VLC table used for encoding. On the other hand, in CABAC, binarization processing is performed on syntax that can take multiple values such as a prediction mode and a conversion coefficient, and binary data obtained by this binarization processing is adaptive according to the occurrence probability. Are arithmetically encoded. Specifically, multiple buffers that hold the occurrence probability of binary values (0 or 1) are prepared, one buffer is selected according to the context, and arithmetic coding is performed based on the occurrence probability recorded in the buffer I do. Further, by updating the occurrence probability of the buffer based on the binary value to be decoded / encoded, an appropriate occurrence probability can be maintained according to the context.

  The moving image decoding apparatus 1 receives encoded data # 1 obtained by encoding a moving image by the moving image encoding apparatus 2. The video decoding device 1 decodes the input encoded data # 1 and outputs the video # 2 to the outside. Prior to detailed description of the moving picture decoding apparatus 1, the configuration of the encoded data # 1 will be described below.

[Configuration of encoded data]
A configuration example of encoded data # 1 that is generated by the video encoding device 2 and decoded by the video decoding device 1 will be described with reference to FIG. The encoded data # 1 exemplarily includes a sequence and a plurality of pictures constituting the sequence.

  The hierarchical structure below the picture layer in the encoded data # 1 is shown in FIG. 3A to 3D are included in the picture layer that defines the picture PICT, the slice layer that defines the slice S, the tree block layer that defines the tree block TBLK, and the tree block TBLK, respectively. It is a figure which shows the CU layer which prescribes | regulates a coding unit (Coding Unit; CU).

(Picture layer)
In the picture layer, a set of data referred to by the video decoding device 1 for decoding a picture PICT to be processed (hereinafter also referred to as a target picture) is defined. As shown in FIG. 3A, the picture PICT includes a picture header PH and slices S _{1 to} S _NS (where NS is the total number of slices included in the picture PICT).

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

  The picture header PH includes a coding parameter group that is referred to by the video decoding device 1 in order to determine a decoding method of the target picture. For example, the encoding mode information (entropy_coding_mode_flag) indicating the variable length encoding mode used in encoding by the moving image encoding device 2 is an example of an encoding parameter included in the picture header PH.

  When entropy_coding_mode_flag is 0, the picture PICT is encoded by CAVLC (Context-based Adaptive Variable Length Coding). When entropy_coding_mode_flag is 1, the picture PICT is encoded by CABAC (Context-based Adaptive Binary Arithmetic Coding).

  The picture header PH is also called a picture parameter set (PPS).

(Slice layer)
In the slice layer, a set of data referred to by the video decoding device 1 for decoding the slice S to be processed (also referred to as a target slice) is defined. As shown in FIG. 3B, the slice S includes a slice header SH and tree blocks TBLK _{1 to} TBLK _NC (where NC is the total number of tree blocks included in the slice S).

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

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

  Further, the slice header SH may include a filter parameter referred to by a loop filter (not shown) included in the video decoding device 1.

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

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

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

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

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

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

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

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

  In addition, the size that each coding node can take depends on the size designation information and the maximum hierarchical depth of the coding node included in the sequence parameter set SPS of the coded data # 1. For example, when the size of the tree block TBLK is 64 × 64 pixels and the maximum hierarchical depth is 3, the coding nodes in the hierarchy below the tree block TBLK have four sizes, that is, 64 × 64. It can take any of a pixel, 32 × 32 pixel, 16 × 16 pixel, and 8 × 8 pixel.

(Tree block header)
The tree block header TBLKH includes an encoding parameter referred to by the video decoding device 1 in order to determine a decoding method of the target tree block. Specifically, as shown in (c) of FIG. 3, tree block division information SP_TBLK that designates a division pattern of the target tree block into each CU, and a quantization parameter difference that designates the size of the quantization step Δqp (qp_delta) is included.

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

  Note that the tree block division information SP_TBLK may not explicitly include the shape or size of the CU. For example, the tree block division information SP_TBLK may be a set of CU division flags (split_coding_unit_flag) that is a flag indicating whether or not the entire target tree block or a partial area of the tree block is divided into four. In that case, the shape and size of each CU can be specified by using the shape and size of the tree block together.

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

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

  Here, before describing specific contents of data included in the coding unit 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 division in the prediction tree: intra prediction and inter prediction.

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

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

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

  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 encoding unit information)
Next, specific contents of data included in the coding unit information CU will be described with reference to FIG. As shown in FIG. 3D, the coding unit information CU specifically includes a skip mode flag SKIP, CU prediction type information Pred_type, PT information PTI, and TT information TTI.

[Skip flag]
The skip flag SKIP is a flag (skip_flag) indicating whether or not the skip mode is applied to the target CU. When the value of the skip flag SKIP is 1, that is, when the skip mode is applied to the target CU. The PT information PTI in the coding unit information CU is omitted. Note that the skip flag SKIP is omitted for the I slice.

[CU prediction type information]
The CU prediction type information Pred_type includes CU prediction method information (PredMode) and PU partition type information (PartMode).

  The CU prediction method information (PredMode) specifies whether to use a skip mode, intra prediction (intra CU), or inter prediction (inter CU) as a predicted image generation method for each PU included in the target CU. Is. Hereinafter, the types of skip, intra prediction, and inter prediction in the target CU are referred to as a CU prediction mode.

  The PU partition type information (PartMode) specifies a PU partition type that is a pattern of partitioning the target coding unit (CU) into each PU. Hereinafter, dividing the target coding unit (CU) into each PU according to the PU division type in this way is referred to as PU division.

  The PU partition type information (PartMode) may be, for example, an index indicating the type of PU partition pattern, and the shape and size of each PU included in the target prediction tree, and the target prediction tree The position may be specified. Note that PU partitioning is also called a prediction unit partitioning type.

  The selectable PU partition types differ depending on the CU prediction method and the CU size. Furthermore, the PU partition types that can be selected are different in each case of inter prediction and intra prediction. Details of the PU partition type will be described later.

  When the slice is not an I slice, the value of the CU prediction method information (PredMode) and the value of the PU partition type information (PartMode) are a CU partition flag (split_coding_unit_flag), a skip flag (skip_flag), a merge flag (merge_flag; described later), and a CU. It may be specified by an index (cu_split_pred_part_mode) that specifies a combination of prediction method information (PredMode) and PU partition type information (PartMode). An index such as cu_split_pred_part_mode is also called a combined syntax (or joint code).

[PT information]
The PT information PTI is information related to the PT included in the target CU. In other words, the PT information PTI is a set of information on each of one or more PUs included in the PT. As described above, since the generation of the predicted image is performed in units of PUs, the PT information PTI is referred to when the moving image decoding apparatus 1 generates a predicted image. As shown in (d) of FIG. 3, the PT information PTI includes PU information PUI _{1 to} PUI _NP (NP is the total number of PUs included in the target PT) including prediction information and the like in each PU.

  The prediction information PUI includes intra prediction information or inter prediction information depending on which prediction method is specified by the prediction type information Pred_mode. Hereinafter, a PU to which intra prediction is applied is also referred to as an intra PU, and a PU to which inter prediction is applied is also referred to as an inter PU.

  The inter prediction information includes a coding parameter that is referred to when the video decoding device 1 generates an inter prediction image by inter prediction.

  Examples of the inter prediction parameters include a merge flag (merge_flag), a merge index (merge_idx), an estimated motion vector index (mvp_idx), a reference image index (ref_idx), an inter prediction flag (inter_pred_flag), and a motion vector residual (mvd). Is mentioned.

  The intra prediction information includes an encoding parameter that is referred to when the video decoding device 1 generates an intra predicted image by intra prediction.

  Examples of intra prediction parameters include an estimated prediction mode flag, an estimated prediction mode index, and a residual prediction mode index.

  In the intra prediction information, a PCM mode flag indicating whether to use the PCM mode may be encoded. When the PCM mode flag is encoded and the PCM mode flag indicates that the PCM mode is used, the prediction process (intra), the conversion process, and the entropy encoding process are omitted. .

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

As shown in FIG. 3D, the TT information TTI includes TT division information SP_TU that designates a division pattern of the target CU into each transform block, and TU information TUI _{1 to} TUI _NT (NT is the target CU). The total number of blocks included).

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

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

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

  Each quantization prediction residual is encoded data generated by the moving image encoding device 2 performing the following processes 1 to 3 on a target block that is a processing target block.

Process 1: DCT transform (Discrete Cosine Transform) of the prediction residual obtained by subtracting the prediction image from the encoding target image;
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;
The quantization parameter qp described above represents the magnitude of the quantization step QP used when the moving image coding apparatus 2 quantizes the transform coefficient (QP = 2 ^{qp / 6} ).

(PU split type)
In the PU division type, if the size of the target CU is 2N × 2N pixels, there are the following eight patterns in total. 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, an area obtained by dividing a symmetric CU is also referred to as a partition.

  4A to 4H specifically illustrate the positions of the boundaries of PU division in the CU for each division type.

  FIG. 4A shows a 2N × 2N PU partition type that does not perform CU partitioning.

  Also, (b), (c), and (d) of FIG. 4 show the partition shapes when the PU partition types are 2N × N, 2N × nU, and 2N × nD, respectively. ing. Hereinafter, partitions when the PU partition type is 2N × N, 2N × nU, and 2N × nD are collectively referred to as a horizontally long partition.

  Further, (e), (f), and (g) of FIG. 4 show the shapes of partitions when the PU partition types are N × 2N, nL × 2N, and nR × 2N, respectively. . Hereinafter, partitions when the PU partition type is N × 2N, nL × 2N, and nR × 2N are collectively referred to as a vertically long partition.

  Further, the horizontally long partition and the vertically long partition are collectively referred to as a rectangular partition.

  Moreover, (h) of FIG. 4 has shown the shape of the partition in case PU partition type is NxN. The PU partition types shown in FIGS. 4A and 4H are also referred to as square partitioning based on the shape of the partition. Further, the PU partition types shown in FIGS. 4B to 4G are also referred to as non-square partitions.

  Also, in (a) to (h) of FIG. 4, the numbers assigned to the respective regions indicate the region identification numbers, and the processing is performed on the regions in the order of the identification numbers. That is, the identification number represents the scan order of the area.

  Also, in FIGS. 4A to 4H, the upper left is the CU reference point (origin).

[Partition type for inter prediction]
In the inter PU, seven types other than N × N ((h) in FIG. 4) are defined among the above eight division types. Note that the above four asymmetric partitions may be called AMP (Asymmetric Motion Partition). In general, a CU divided by asymmetric partitions includes partitions having different shapes or sizes. Symmetric partitioning may also be referred to as a symmetric partition. In general, a CU divided by a symmetric partition includes a partition having the same shape and size.

  The specific value of N described above is defined by the size of the CU to which the PU belongs, and specific values of nU, nD, nL, and nR are determined according to the value of N. For example, a 128 × 128 pixel inter-CU includes 128 × 128 pixels, 128 × 64 pixels, 64 × 128 pixels, 64 × 64 pixels, 128 × 32 pixels, 128 × 96 pixels, 32 × 128 pixels, and 96 × It is possible to divide into 128-pixel inter PUs.

[Partition type for intra prediction]
In the intra PU, the following two types of division patterns are defined. That is, there are a division pattern 2N × 2N in which the target CU is not divided, that is, the target CU itself is handled as one PU, and a pattern N × N in which the target CU is symmetrically divided into four PUs.

  Therefore, in the intra PU, the division patterns (a) and (h) can be taken in the example shown in FIG.

  For example, an 128 × 128 pixel intra CU can be divided into 128 × 128 pixel and 64 × 64 pixel intra PUs.

  In the case of an I slice, the coding unit information CU may include an intra partition mode (intra_part_mode) for specifying a PU partition type (PartMode).

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

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

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

  In the following, a picture (frame), a slice, a tree block, a block, and a PU to be decoded are referred to as a target picture, a target slice, a target tree block, a target block, and a target PU, respectively. .

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

(Configuration of video decoding device)
Referring to FIG. 2 again, the schematic configuration of the moving picture decoding apparatus 1 will be described as follows. FIG. 2 is a functional block diagram showing a schematic configuration of the moving picture decoding apparatus 1.

  As shown in FIG. 2, the moving picture decoding apparatus 1 includes a decoding module 10, a CU information decoding unit 11, a PU information decoding unit 12, a TU information decoding unit 13, a predicted image generation unit 14, an inverse quantization / inverse conversion unit 15, A frame memory 16 and an adder 17 are provided.

[Decryption module]
The decoding module 10 performs a decoding process for decoding a syntax value from binary. More specifically, the decoding module 10 decodes a syntax value encoded by an entropy encoding method such as CABAC and CAVLC based on encoded data and a syntax type supplied from a supplier, Returns the decrypted syntax value to the supplier.

  In the example shown below, the sources of encoded data and syntax type are the CU information decoding unit 11, the PU information decoding unit 12, and the TU information decoding unit 13.

  The case where the decoding module 10 performs decoding by the CAVLC encoding method will be schematically described with reference to FIG. FIG. 5 is a diagram showing an outline of CAVLC encoding / decoding processing using a variable table.

  The decoding module 10 performs a decoding process according to a VLC method for decoding a syntax value from a binary string (bin) of input encoded data.

  The decoding module 10 decodes the code number from the bit string of the encoded data using the VLC method corresponding to the syntax and context. The VLC method is a method for associating a bit string with a code number. Examples of the VLC method include a method using a table that associates a bit string with a code number, a method using a derivation formula for deriving a code number from the bit string, and the like.

  Further, the decoding module 10 refers to the variable table in which the code number and the syntax value are associated with each other, and derives the syntax value corresponding to the decoded code number.

  Further, the decoding module 10 adaptively updates the variable table according to the decoding result of the code number. The update of the variable table refers to, for example, a process of exchanging a syntax value associated with a certain code number and a syntax value associated with a code number smaller than the certain code number.

  Thus, the process of adaptively updating the variable table according to the code number decoding result is referred to as a variable table adaptive process. Details of the variable table adaptation processing will be described later.

  In this way, the decoding process in the decoding module 10 is completed. Details of the decryption module 10 will be described later.

[CU information decoding unit]
The CU information decoding unit 11 uses the decoding module 10 to perform decoding processing at the tree block and CU level on the encoded data # 1 for one frame input from the moving image encoding device 2. Specifically, the CU information decoding unit 11 decodes the encoded data # 1 according to the following procedure.

  First, the CU information decoding unit 11 refers to various headers included in the encoded data # 1, and sequentially separates the encoded data # 1 into slices and tree blocks.

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

  Then, the CU information decoding unit 11 refers to the tree block division information SP_TBLK included in the tree block header TBLKH, and divides the target tree block into CUs.

  Next, the CU information decoding unit 11 acquires coding unit information (hereinafter referred to as CU information) corresponding to the CU obtained by the division. The CU information decoding unit 11 performs the decoding process of the CU information corresponding to the target CU, with each CU included in the tree block as the target CU in order.

  That is, the CU information decoding unit 11 demultiplexes the TT information TTI related to the conversion tree obtained for the target CU and the PT information PTI related to the prediction tree obtained for the target CU.

  The TT information TTI includes the TU information TUI corresponding to the TU included in the conversion tree as described above. Further, as described above, the PT information PTI includes the PU information PUI corresponding to the PU included in the target prediction tree.

  The CU information decoding unit 11 supplies the PT information PTI obtained for the target CU to the PU information decoding unit 12. Further, the CU information decoding unit 11 supplies the TT information TTI obtained for the target CU to the TU information decoding unit 13.

[PU information decoding unit]
The PU information decoding unit 12 uses the decoding module 10 to perform decoding processing at the PU level for the PT information PTI supplied from the CU information decoding unit 11. Specifically, the PU information decoding unit 12 decodes the PT information PTI by the following procedure.

  The PU information decoding unit 12 refers to the PU partition type information Part_type to determine the PU partition type in the target prediction tree. Subsequently, the PU information decoding unit 12 performs a decoding process of PU information corresponding to the target PU, with each PU included in the target prediction tree as a target PU in order.

  That is, the PU information decoding unit 12 performs a decoding process on each parameter used for generating a predicted image from PU information corresponding to the target PU.

  The PU information decoding unit 12 supplies the PU information decoded for the target PU to the predicted image generation unit 14.

[TU information decoding unit]
The TU information decoding unit 13 uses the decoding module 10 to perform decoding processing at the TU level for the TT information TTI supplied from the CU information decoding unit 11. Specifically, the TU information decoding unit 13 decodes the TT information TTI by the following procedure.

  The TU information decoding unit 13 divides the target conversion tree into nodes or TUs with reference to the TT division information SP_TU. Note that the TU information decoding unit 13 recursively performs TU division processing if it is specified that further division is performed for the target node.

  When the division process ends, the TU information decoding unit 13 performs the decoding process of the TU information corresponding to the target TU, with each TU included in the target prediction tree as the target TU in order.

  That is, the TU information decoding unit 13 performs a decoding process on each parameter used for restoring the transform coefficient from the TU information corresponding to the target TU.

  The TU information decoding unit 13 supplies the TU information decoded for the target TU to the inverse quantization / inverse transform unit 15.

[Predicted image generator]
The predicted image generation unit 14 generates a predicted image based on the PT information PTI for each PU included in the target CU. Specifically, the prediction image generation unit 14 performs intra prediction or inter prediction for each target PU included in the target prediction tree according to the parameters included in the PU information PUI corresponding to the target PU, thereby generating a decoded image. A predicted image Pred is generated from a certain local decoded image P ′. The predicted image generation unit 14 supplies the generated predicted image Pred to the adder 17.

  A method in which the predicted image generation unit 14 generates a predicted image of a PU included in the target CU based on motion compensation prediction parameters (motion vector, reference image index, inter prediction flag) is as follows.

  When the inter prediction flag indicates single prediction, the predicted image generation unit 14 generates a predicted image corresponding to the decoded image located at the location indicated by the motion vector of the reference image indicated by the reference image index.

  On the other hand, when the inter prediction flag indicates bi-prediction, the predicted image generation unit 14 generates a predicted image by motion compensation for each of the two sets of reference image indexes and motion vectors, and calculates an average. Alternatively, the final predicted image is generated by weighting and adding each predicted image based on the display time interval between the target picture and each reference image.

[Inverse quantization / inverse transform unit]
The inverse quantization / inverse transform unit 15 performs an inverse quantization / inverse transform process on each TU included in the target CU based on the TT information TTI. Specifically, the inverse quantization / inverse transform unit 15 performs inverse quantization and inverse orthogonal transform on the quantization prediction residual included in the TU information TUI corresponding to the target TU for each target TU included in the target conversion tree. By doing so, the prediction residual D for each pixel is restored. Here, the orthogonal transform refers to an orthogonal transform from the pixel region to the frequency region. Therefore, the inverse orthogonal transform is a transform from the frequency domain to the pixel domain. Examples of inverse orthogonal transform include inverse DCT transform (Inverse Discrete Cosine Transform), inverse DST transform (Inverse Discrete Sine Transform), and the like. The inverse quantization / inverse transform unit 15 supplies the restored prediction residual D to the adder 17.

[Frame memory]
Decoded decoded images P are sequentially recorded in the frame memory 16 together with parameters used for decoding the decoded images P. In the frame memory 16, at the time of decoding the target tree block, decoded images corresponding to all tree blocks decoded before the target tree block (for example, all tree blocks preceding in the raster scan order) are stored. It is recorded. Examples of decoding parameters recorded in the frame memory 16 include CU prediction method information (PredMode).

[Adder]
The adder 17 adds the predicted image Pred supplied from the predicted image generation unit 14 and the prediction residual D supplied from the inverse quantization / inverse transform unit 15 to thereby obtain the decoded image P for the target CU. Generate.

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

(Details of CU information decoding unit and decoding module)
Next, configuration examples of the CU information decoding unit 11 and the decoding module 10 will be described with reference to FIG. FIG. 1 is a functional block diagram illustrating a configuration for decoding CU prediction information, that is, a configuration of a CU information decoding unit 11 and a decoding module 10 in the moving image decoding apparatus 1.

  Hereinafter, the configuration of each unit will be described in the order of the CU information decoding unit 11 and the decoding module 10.

(CU information decoding unit)
As shown in FIG. 1, the CU information decoding unit 11 includes a combined syntax determining unit (additional information restoring unit) 111, a PU partition type definition table 113, and a PU partition type residual information definition table 114.

  The PU partition type definition table 113 and the PU partition type residual information definition table 114 constitute a definition table 112 of a combined syntax (cu_split_pred_part_mode).

[PU partition type definition table]
The PU partition type definition table 113 includes a syntax value of the combined syntax cu_split_pred_part_mode, a CU partition flag (split_coding_unit_flag), a skip flag (skip_flag), a merge flag (merge_flag), CU prediction method information (PredMode), and PU partition type information. It is a table which matches the combination of (PartMode).

  Since each of the CU partition flag, skip flag, merge flag (merge_flag), CU prediction method information (PredMode), and PU partition type information (PartMode) has already been described, the description thereof is omitted.

  In the PU partition type definition table 113, the PU partition type is defined to belong to any group of square, horizontally long rectangle, and vertically long rectangle. That is, in the PU partition type definition table 113, PU partition types (2N × N / 2N × nU / 2N × nD) including horizontally long rectangular PUs are grouped into one group and an index indicating the group is assigned. The same applies to the PU division type (N × 2N / nL × 2N / nR × 2N) including the vertically long rectangular PU. In the following, a PU split type group including a horizontally long rectangular PU is referred to as a horizontally long rectangular PU group, and a PU split type group including a vertically long rectangular PU is referred to as a vertically long rectangular PU group.

  The PU partition type definition table 113A, which is one configuration example of the PU partition type definition table 113, will be described with reference to FIG. FIG. 6 is a diagram illustrating a configuration example of the PU partition type definition table 113A when CUWidth> 8.

  As shown in FIG. 6, in the PU partition type definition table 113A, a combination of split_coding_unit_flag, skip_flag, merge_flag, PredMode, and PartMode is defined in association with cu_split_pred_part_mode. “-” In the figure indicates that no value is set in such a combination. That is, when split_coding_unit_flag is 1, CU partitioning is further performed in the CU, and therefore the values of skip_flag, merge_flag, PredMode, and PartMode are not set.

  Further, for example, when cu_split_pred_part_mode = 3, CU partitioning, skipping, and merging are not performed (split_coding_unit_flag, skip_flag, and merge_flag are all “0”), PredMode = MODE_INTER, PartMode = PART_2N × 2N Has been.

  In addition, in cu_split_pred_part_mode = 4, 5, “escape” indicates that additional syntax values are decoded in order to specify the PU partition type belonging to the group. The additional syntax value is a syntax rem_part_mode defined in the PU partition type residual information definition table 114 shown below. rem_part_mode indicates information for specifying which PU partition type belongs to the same PU group.

[PU partition type residual information definition table]
The PU partition type residual information definition table 114 is a table that associates the value of rem_part_mode that is additionally decoded with respect to cu_split_pred_part_mode for which “escape” is specified, with PartMode.

  The PU partition type residual information definition table 114A, which is one configuration example of the PU partition type residual information definition table 114, will be described with reference to FIG. FIG. 7 is a diagram illustrating a configuration example of the PU partition residual information definition table 114A when CUWidth> 8.

  As shown in FIG. 7, in the PU partition type residual information definition table 114A, the association between rem_part_mode and PartMode is defined for cu_split_pred_part_mode in which “escape” is specified.

  That is, in the PU partition type residual information definition table 114A, when the value of cu_split_pred_part_mode indicates a horizontally long rectangular PU group ("4" in FIG. 6) or when it indicates a vertically long rectangular PU group ("5 in FIG. 6)" For “)”, association between rem_part_mode to be additionally decoded and PartMode is defined.

  For example, in the PU partition type residual information definition table 114A, when cu_split_pred_part_mode = 4 (horizontal rectangular PU group), rem_part_mode takes a value of “0”, “1”, or “2”, and PartMode “PART — 2N × N ”,“ PART — 2N × nU ”, and“ PART — 2N × nD ”are defined.

  In FIG. 7, the syntax value (value) of rem_part_mode and the bit string (binary) assigned to the value are shown together.

  Further, it is preferable that a shorter code is assigned to the value of rem_part_mode of the symmetric partition than the value of rem_part_mode of the asymmetric partition. For example, as shown in FIG. 7, it is preferable that codes shorter than 2N × nU and 2N × nD are assigned to 2N × N.

  This is because the probability of occurrence of a symmetric partition statistically tends to be higher than the probability of occurrence of an asymmetric partition. In this way, it is possible to reduce the code amount by assigning a short code to a symmetric partition having a high probability of occurrence.

  Moreover, it is preferable that a short code is assigned by a PU partition type having a small number of partitions. For example, for a PU partition type that divides a 2N × 2N CU into two 2N × N size PUs, the code is shorter than a PU partition type that divides into four 2N × 0.5N PUs. Is preferably assigned.

[Join syntax determination unit]
The combined syntax determination unit 111 uses the decoding module 10 to decode cu_split_pred_part_mode, and based on the decoded cu_split_pred_part_mode, refers to the definition table 112 of the combined syntax (cu_split_pred_part_mode) to determine CU prediction scheme information (PredMode) and PU A value such as a division type (PartMode) is determined.

  The combined syntax determination unit 111 supplies the encoded data of the CU prediction mode and the syntax type cu_split_pred_part_mode to the decoding module 10. Also, the combined syntax determination unit 111 acquires the decoded syntax value of cu_split_pred_part_mode from the decoding module 10.

  Then, the combined syntax determination unit 111 derives a PU partition type value from the value of cu_split_pred_part_mode based on the definition table 112 of the combined syntax (cu_split_pred_part_mode). Further, in the case of cu_split_pred_part_mode for which “escape” is specified, the decoding module 10 additionally decodes rem_part_mode, and refers to the PU partition type residual information definition table 114A using the decoded rem_part_mode, thereby final PU partitioning Derive the type value. Details of the operation of the combined syntax determination unit 111 will be described later.

  Note that the CU information decoding unit 11 uses the PU size table DF11 as shown in FIG. 8 to determine the number of PUs and the PU size after the combined syntax determination unit 111 derives the PU partition type value. May be.

  FIG. 8 is described as follows. In the PU size table DF11 shown in FIG. 8, the number and size of PUs are defined according to the size of the CU and the PU partition type (intra CU and inter CU). Note that “d” in the table indicates the division depth of the CU.

  In the PU size table DF11, four sizes of 64 × 64, 32 × 32, 16 × 16, and 8 × 8 are defined as CU sizes. Further, the division depth d of the CU is a value indicating the division depth with respect to the maximum size of the CU. When the maximum CU size is 64 × 64, d = 0 is 64 × 64, d = 1 is 32 × 32, d = 2 indicates 16 × 16, and d = 3 indicates 8 × 8 CU size. If the maximum CU size is determined, the CU size and the division depth of the CU correspond one-to-one. Therefore, the determination process based on the CU size described below may be realized as a determination process based on the CU division depth. Conversely, the determination process based on the CU division depth may be realized as a determination process based on the CU size.

  In the PU size table DF11, the number and size of PUs in each PU partition type are defined for the size of the CU.

  For example, in the case of a 64 × 64 inter CU and 2N × N division, there are two PUs and both sizes are 64 × 32.

  Further, in the case of a 64 × 64 inter CU and 2N × nU division, there are two PUs and the sizes are 64 × 16 and 64 × 48.

  Further, in the case of an 8 × 8 intra CU and N × N division, the number of PUs is 4 and the sizes are all 4 × 4.

  Note that the PU partition type of the skip CU is estimated to be 2N × 2N. Further, in the table, a portion indicated by “−” indicates that the PU partition type cannot be selected.

  That is, when the CU size is 8 × 8, PU partition types of asymmetric partitions (2N × nU, 2N × nD, nL × 2N, and nR × 2N) cannot be selected in the inter CU. In the case of an inter CU, an N × N PU partition type cannot be selected.

  Also, in intra prediction, it is possible to select an N × N PU partition type only when the CU size is 8 × 8.

  In general, when the CU size is the minimum CU size, the asymmetric partition is set to be unselectable.

(Decryption module)
As illustrated in FIG. 1, the decoding module 10 includes a combined syntax decoding unit (decoding unit, prediction unit division type group acquisition unit, additional information restoration unit, arithmetic decoding unit) 1011, a variable table storage unit 1012, and a VLC scheme selection unit. 1013, a variable table selection unit 1014, and a variable table adaptation unit 1015 (adaptive processing means).

[Combined syntax decoding unit]
Based on the encoded data and syntax type “cu_split_pred_part_mode” supplied from the combined syntax determining unit 111, the combined syntax decoding unit 1011 is configured to use a VLC scheme selection unit 1013, a variable table selection unit 1014, and a variable table adaptation unit 1015. And the syntax value is decoded from the binary included in the encoded data. Specific operation details of the combined syntax decoding unit 1011 will be described later.

[Variable table storage unit]
The variable table storage unit 1012 stores variable tables corresponding to various syntaxes. One variable table does not necessarily correspond to one type of syntax. For example, different variable tables may be associated with the same syntax according to the CU size.

  In the variable table, a code number and a syntax value are associated with each other. In the variable table, the correspondence between the code number and the syntax value is updated according to the code number to be decoded.

  For example, a variable table corresponding to the syntax type “cu_split_pred_part_mode (join syntax)” will be described as follows. That is, the variable table storage unit 1012 has 8 × 8 CU combined syntax 1012A, 16 × 16 CU combined syntax 1012B, 32 × 32 CU combined syntax 1012C, and 64 × 64 CU combined syntax 1012D according to the CU size. Four are defined.

[VLC method selector]
The VLC method selection unit 1013 sets the VLC method used for decoding the code number from the encoded data according to the syntax type based on the default definition.

  For example, for the syntax type “cu_split_pred_part_mode”, the VLC method selection unit 1013 sets the maximum value based on the size of the target CU (in other words, the division depth of the target CU (CU depth, depth)), and the maximum The VLC method is selected according to the value. Specifically, when the CU size is 8 × 8 (CU depth is 3), the VLC method selection unit 1013 sets the maximum value to 5 and the CU size is larger than 8 × 8 (CU depth is 3). If it is smaller, the maximum value is set to 6. Then, the VLC scheme selection unit 1013 selects a truncated unary code corresponding to the set maximum value as the VLC scheme.

  Further, for example, the VLC scheme selection unit 1013 selects a truncated unary code corresponding to the maximum value 2 for the syntax type “rem_part_mode”.

  The maximum value to be set is preferably a number obtained by subtracting 1 from the number of values that each syntax value can take. In the case of rem_part_mode, it is a PU group applicable to a specific CU size, and is preferably a value obtained by subtracting 1 from the number of types of PU partition types belonging to a PU group including a rectangle in the same direction.

  In the case of the PU division type belonging to the horizontally long rectangular PU group, there are three types of 2N × N, 2N × nU, and 2N × nD. In this case, it is preferable to set the maximum value to 2.

  In addition, the VLC method selection unit 1013 notifies the combined syntax decoding unit 1011 of the set VLC method.

  Note that the decoding of the code number (codeNum) by the truncated unary code in the case of the maximum value cMax can be realized by the process defined by the following pseudo code. Here, read_bits (1) is a function that reads a 1-bit binary from the encoded data and returns the value.

leadingZeroBits = -1
for (b = 0;! b && leadingZeroBits <cMax; leadingZeroBits ++)
b = read_bits (1)
codeNum = leadingZeroBits

[Variable table selection section]
The variable table selection unit 1014 selects whether or not to apply a variable table and a variable table to be applied according to the type of target syntax based on a predetermined definition.

  Specifically, the variable table selection unit 1014 determines to apply a variable table for the syntax type “cu_split_pred_part_mode”, and selects a variable table corresponding to the CU size from the variable table storage unit 1012.

  In addition, the variable table selection unit 1014 determines not to apply the variable table for the syntax type “rem_part_mode”.

  Also, the variable table selection unit 1014 notifies the combined syntax decoding unit 1011 of whether or not the variable table is applied and the selected variable table.

[Supplementary information about variable table selection unit and variable table storage unit]
(1) As described above, the variable table selection unit 1014 has a syntax (for example, a join syntax (cu_split_pred_part_mode)) that includes information for selecting whether the PU partition type belongs to a square, a horizontally long rectangle, or a vertically long group. ), A variable table is applied, and it is preferable not to apply a variable table to information (for example, rem_part_mode) that specifies which PU partition type is a horizontal rectangular (vertical rectangular) PU group. .

This is because the former is more likely to have the same syntax value than the latter. For example, cu_split_pred_part_mode has a higher probability that the same syntax value is continuous than rem_part_mode.
(2) The variable table selection unit 1014 and the variable table storage unit 1012 may not be configured to apply a variable table in all CU sizes with respect to cu_split_pred_part_mode. You may comprise so that a variable table may be applied only to a part of CU size. For example, the variable table selection unit 1014 may be configured not to apply a variable table for 64 × 64 CUs, but to apply a variable table for other CU sizes.

  In addition, since the range (maximum value) of cu_split_pred_part_mode differs between 8 × 8 CUs and other CUs, it is preferable to use different variable tables.

If it is more generalized, the CU_split_pred_part_mode value range (maximum value) differs between the CU of the minimum size and other CUs. Therefore, it is preferable to use different variable tables for the minimum size CU and other CUs.
(3) Although it has been described that the variable table selection unit 1014 selects a variable table according to the CU size, specifically, the variable table selection unit 1014 can select a variable table as follows. it can.

  First, the variable table selection unit 1014 selects the variable table corresponding to the CU size using the following equation (1) that derives the variable table identification information (table) from the depth of the CU. Good.

table = SplitTableCounter [depth] (1)
In the above formula (1), SplitTableCounter is a function that returns a variable table according to the depth (depth) of the CU as an argument.
(4) Regarding the cu_split_pred_part_mode, the variable table selection unit 1014 and the variable table storage unit 1012 may be configured to share the variable table among some CU sizes. As a result, the memory size of the variable table can be reduced.

  Specifically, the variable table selection unit 1014 may select the variable table as follows in a configuration in which the variable table is shared.

  First, an intermediate selection table mtbl for selecting a variable table is provided. In the selection table mtbl, the ID of the variable table selected at each CU depth is set for each LCU size. The selection table (mtbl) is defined such that the same value (intermediate table ID) is set for CUs sharing the variable table.

  In addition, the variable table selection unit 1014 obtains the intermediate table ID (id) by referring to the selection table (mtbl) according to the index (log2_lcu_size_minus4) indicating the LCU size and the CU depth (depth).

  An example of the selection table mtbl and pseudo code for deriving identification information of the variable table are shown below.

<< Pseudo Code 1 >> Example shared by 16 × 16 CU, 32 × 32 CU, and 64 × 64 CU
log2_lcu_size_minus4 = log2 (LCU size) -4 // 0: 16x16, 1: 32x32, 2: 64x64… (A)
mtbl [3] [4] = {
{0, 1, -1, -1}, // LCU = 16x16
{0, 0, 1, -1}, // LCU = 32x32
{0, 0, 0, 1}, // LCU = 64x64… idx = 0 for 64x64CU, 32x32CU, 16x16CU, id = 1 for 8x8CU
} (B)
id = mtbl [LCU_size_idx] [depth] // LCU_size_idx = log2_lcu_size_minus4… (C)
table = SplitTableCounter [id] (D)
Row (A): A value obtained by subtracting 4 from the logarithmic value of the LCU size is used as an index indicating the LCU size. For convenience of description, LCU_size_idx = log2_lcu_size_minus4.

  Line (B): mtbl is defined. Mtbl is defined for each CU size. Also, mtbl is defined as an array of 3 rows and 4 columns.

  The first line defines LCU = 16x16. The first column defines that id = 0 when depth = 0, that is, 16 × 16 CU. The second column defines that id = 1 when depth = 1, that is, 8 × 8 CU. In mtbl, depth = 0, 1, 2, 3 can be defined, but a column in which “-1” is set in LCU = 16x16 or the like indicates that such depth does not exist.

  The second line defines LCU = 32x32. In the second line, the same id = 0 is set between 32 × 32 CU with depth = 0 and 16 × 16 CU with depth = 1. Also, id = 1 is set for an 8 × 8 CU with depth = 2.

  The third line defines LCU = 64x64. When the LCU size is 64, depth = 0, 1, 2, and 3 correspond to 64x64CU, 32x32CU, 16x16CU, and 8x8CU, respectively. In the third line, the same id = 0 is set among 64 × 64 CU, 32 × 32 CU, and 16 × 16 CU. Moreover, id = 1 different from these CU sizes is set for the 8 × 8 CU.

  Line (C): Referring to mtbl according to LCU_size_idx and depth, the intermediate table ID is acquired.

  Row (D): The final table ID (table) is acquired by applying id to the SplitTableCounter function.

<< Pseudo code 2 >> Example of sharing between 32 × 32 CU and 64 × 64 CU (only mtbl)
mtbl [3] [4] = {
{1, 2, -1, -1}, // 16x16CU has id = 1, 8x8CU has id = 2
{0, 1, 2, -1}, // 32x32CU has id = 0, 16x16CU has id = 1, 8x8CU has id = 2
{0, 0, 1, 2} // 64x64CU, 32x32CU has id = 0, 16x16CU has id = 1, 8x8CU has id = 2
}
Similarly to the pseudo code 1, when the table of id = 0 is shared by 32 × 32 CU and 64 × 64 CU, it can be defined as described above. In the pseudo code 2, separate tables are set for 16 × 16 CU and 8 × 8 CU, respectively.

[Variable table adaptor]
The variable table adaptation unit 352 performs variable table adaptation processing on the selected variable table based on the decoded code number.

  The variable table adaptation process performed by the variable table adaptation unit 352 will be described with reference to FIG.

As shown in FIG. 9, the variable table 1012 corresponds to a code number codeNum and a syntax value S _x (x is 0, 1, 2,..., Hereinafter, S _x is referred to as a variable table element). It is an attached table. Note that _Sx may be a table index indicating a syntax value.

As he is shown on the left side of FIG. 9, the _{S 2} of codeNum = 2, "0" is, elements _{S 3} of codeNum = 3, and "2" are stored.

Here, when the code number (codeNum) “3” is decoded, the variable table adaptation unit 352 replaces the element S ₃ with codeNum = ₃ and the element S ₂ with codeNum = 2 (hereinafter, this replacement is swapped). Called). As a result, the element S ₂ = 2 and the element S ₃ = 0 are obtained.

The fact that the element S ₃ with codeNum = 3 has been decoded can be estimated as a situation where the occurrence probability of the element S ₃ is high. The variable table adaptation unit 352 performs the swap in the variable table, and associates codeNum = 2, which is a smaller code number, with the element “0” estimated to have a high probability of occurrence.

(Process flow)
The processing flow of the combined syntax determination unit 111 and the combined syntax decoding unit 1011 will be described below with reference to FIGS. 10 and 11.

[Join syntax determination unit]
The processing flow of the combined syntax determination unit 111 will be described with reference to FIG. FIG. 10 is a flowchart showing the flow of prediction mode determination processing in the combined syntax determination unit 111.

  First, the combined syntax determination unit 111 accesses the combined syntax decoding unit 1011 to perform CU partition flag (split_coding_unit_flag), skip flag (skip_flag), merge flag (merge_flag), CU prediction method information (PredMode), and PU A syntax value of the binding syntax cu_split_pred_part_mode related to the combination of the split types (PartMode) is acquired (S11).

  Next, the join syntax determination unit 111 refers to the PU partition definition table 113 using the syntax value of cu_split_pred_part_mode, and refers to the CU partition flag (split_coding_unit_flag), skip flag (skip_flag), merge flag (merge_flag), and Each value of CU prediction method information (PredMode) is derived (S12).

  Next, the combined syntax determination unit 111 determines whether the value of the CU partition flag is “1 (CU partition)” (S13).

  When the value of the CU partitioning flag is “1” (YES in S13), the combined syntax determination unit 111 applies CU partitioning to the target CU and sets each divided CU as the target CU (S14), in order. The process is started (return to S11).

  On the other hand, when the value of the CU split flag is not “1” (NO in S13), the connection syntax determination unit 111 determines whether or not the value of cu_split_pred_part_mode indicates a horizontally long rectangular PU group (S15).

  When the value of cu_split_pred_part_mode indicates a horizontally long rectangular PU group (YES in S15; for example, when the CU size is larger than 8 × 8 and the value of cu_split_pred_part_mode is “4”), the combined syntax determination unit 111 The combined syntax decoding unit 1011 is accessed to obtain the syntax value of the PU partition type residual information (rem_part_mode) (S17), and the process proceeds to S18.

  On the other hand, when the value of cu_split_pred_part_mode does not indicate a horizontally long rectangular PU group (NO in S15), the combined syntax determination unit 111 further determines whether or not the value of cu_split_pred_part_mode indicates a vertically long rectangular PU group ( S16).

  When the value of cu_split_pred_part_mode indicates a vertically long rectangular PU group (YES in S16; for example, when the CU size is larger than 8 × 8 and the value of cu_split_pred_part_mode is “5”)), the combined syntax determining unit 111 The combined syntax decoding unit 1011 is accessed to acquire the syntax value of the PU partition type residual information (rem_part_mode) (S17), and the process proceeds to S18.

  On the other hand, when the value of cu_split_pred_part_mode does not indicate a vertically long rectangular PU group (NO in S16), the combined syntax determination unit 111 advances the process to S18.

  The combined syntax determination unit 111 derives the value of PartMode based on the value of cu_split_pred_part_mode and the value of rem_part_mode if decoded in S17 (S18), and ends the process.

[Combined syntax decoding unit]
The processing flow of the combined syntax decoding unit 1011 will be described with reference to FIG. FIG. 11 is a flowchart showing the flow of prediction mode decoding processing in the combined syntax decoding unit 1011.

  First, the combined syntax decoding unit 1011 accesses the VLC method selection unit 1013 and sets the VLC method selected by the VLC method selection unit 1013 (S21).

  Next, the combined syntax decoding unit 1011 decodes the code number from the encoded data using the set VLC method (S22).

  Next, the combined syntax decoding unit 1011 accesses the variable table selection unit 1014, acquires whether or not the variable table is applied to the syntax to be restored, and determines whether or not to apply the variable table. (S23).

  When a variable table is applied (YES in S23), the combined syntax decoding unit 1011 accesses the variable table selection unit 1014, acquires the variable table selected by the variable table selection unit 1014, and derives the syntax value. It is set as a variable table used for this (S24).

  Subsequently, the combined syntax decoding unit 1011 refers to the set variable table and acquires a syntax value corresponding to the decoded code number (S25).

  Further, the combined syntax decoding unit 1011 supplies the variable table and code number to the variable table adaptation unit 1015 and instructs execution of the variable table adaptation process (S26).

  On the other hand, when the variable table is not applied (NO in S23), the combined syntax decoding unit 1011 sets the code number value as the syntax value (S27).

  When the syntax value is determined in S25 or S27, the combined syntax decoding unit 1011 outputs the syntax value (S28) and ends the process.

(Action / Effect)
As described above, the moving image decoding apparatus 1 generates a predicted image for each PU obtained by dividing a CU into one or more numbers by a predetermined PU partition type, and restores the image. As the predetermined PU partition type, a plurality of rectangular PU partition types that are PU partition types into rectangular PUs exist, and a PU group to which two or more of the rectangular PU partition types belong is defined, and the target CU In addition, when the rectangular PU partition type belonging to the PU group is restored, a variable table adaptation unit 1015 that adaptively processes so that codes shorter than before decoding are decoded for each of the rectangular PU partition types belonging to the PU group. It is a configuration.

  With the above configuration, the following effects (1) to (3) are obtained.

(1) Code amount reduction According to the above configuration, for example, when the PU partition type to which the horizontally long rectangular PU group belongs (for example, when 2N × N is decoded, the syntax value corresponding to the horizontally long rectangular PU group is more The variable table is updated so that a smaller code number is assigned.

  Therefore, the code amount can be reduced in a situation where PU division types belonging to the horizontally long rectangular PU group are continuously generated.

  The above situation will be described in more detail with reference to FIGS. 12 and 13 as follows.

  There are also situations where some related PU partition types occur consecutively so that the same PU partition type is likely to occur continuously due to the local nature of the image.

  For example, as shown in FIG. 12, in the region where the edge E1 close to the horizontal exists, the probability of occurrence of all PU partition types including a horizontally long PU is increased. FIG. 12 shows an example of a situation in which different types of horizontally long rectangular PU partition types occur successively.

  Further description of FIG. 12 is as follows. In the figure, six 16 × 16 size encoding units from cu11 to cu16 are arranged in a horizontal row. The scan order is assumed to be the order of cu11 to cu16.

  Further, in the region of cu11 to cu16, there is a substantially horizontal and rightward edge E1. At this time, the PU partition type: 2N × nD is selected in cu11. In cu12 to cu15, 2N × N is selected. In cu16, 2N × nU is selected.

  As described above, in the region where the edge E1 that is substantially horizontal and rises to the right exists, there is a situation in which any PU partition type belonging to the horizontally long PU group is continuously selected.

  In such a situation, it can be said that the 2N × N PU partition type that is a symmetric partition tends to be selected continuously in the middle of the region.

  Further, another example of a situation in which different types of horizontally long rectangular PU partition types occur successively will be described with reference to FIG.

  In FIG. 13, four 32 × 32 size cu22s (tree blocks) including coding units are adjacent to the right side of the 32 × 32 size cu21. Assume that the scan order is the order of cu21 and cu22. An edge E1 that is nearly horizontal exists above cu21 and cu22.

  In cu21, a 2N × nU PU partition type is set, and an edge E1 exists in the upper partition.

  Further, cu22 includes four cu220 to cu223 that are four 16 × 16 CUs. The scan order is assumed to be the order of cu220 to cu223. In cu220 and cu221, a 2N × N PU partition type is set, and an edge E1 exists in the upper partition.

  Also, 2N × 2N PU partition types are set for cu222 and cu223.

  As shown in FIG. 13, even when the encoding unit sizes are different, there are situations in which different types of horizontally long rectangular PU partition types occur successively.

(2) Size reduction of variable table According to the above configuration, since the syntax value corresponding to the horizontally long (vertically long) rectangular PU group is used as an element of the variable table, the syntax value corresponding to each PU partition type is set to each variable table. The size of the variable table can be reduced as compared with the case of using the element.

(3) Algorithm sharing when AMP is used and when not used AMP (horizontal rectangle: 2N × nU / 2N × nD, vertical rectangle: nL × 2N / nR × 2N) is used regardless of whether or not cu_split_pred_part_mode is decoded ( There is no need to change the variable table (related to VLC).

  According to the above configuration, rem_part_mode may be decoded according to whether or not AMP can be used. That is, when AMP can be used, rem_part_mode is decoded, and when AMP cannot be used, rem_part_mode is not decoded.

  Therefore, it is possible to easily limit the degree of freedom of the PU division type (whether AMP can be used) without significantly changing the configuration.

  Note that the availability of AMP is transmitted from the encoder side by a flag (for example, sps_disable_amp_split) that prohibits AMP division in SPS, for example.

(Syntax configuration example)
Next, a configuration example of syntax applied to the video decoding device 1 will be described. First, an example of syntax in Non-Patent Document 1 is shown using FIG. FIG. 14 is a diagram showing a syntax table SYN100 at a coding tree level (tree block layer). The operation on the encoder side will be described below. In FIG. 14, x0 and y0 indicate the coordinates of the upper left pixel in the CU to be processed. The same applies to FIGS. 15 and 16 described later. 14 to 16, “A && B” indicates an AND operation of “A and B”, and “A || B” indicates an OR operation of “A or B”.

  As shown in FIG. 14, in the syntax table SYN100, entropy_coding_mode_flag is “0” (corresponding to “! Entropy_coding_flag” of SYN1001), and the slice type is not I slice (“slice_type! = I” of SYN1001). In the case of correspondence), cu_split_pred_part_mode is decoded (SYN1002). In other words, CU_split_pred_part_mode is decoded when CAVLC is applied as the entropy coding method and the slice is a non-I slice (B slice or P slice).

  Next, a configuration example of a syntax table applied to the video decoding device 1 will be described with reference to FIGS. 15 and 16. FIG. 15 is a diagram illustrating a configuration example of the syntax table SYN11 at the coding tree level (tree block layer).

  The syntax table SYN11 shown in FIG. 15 will be described. Since SYN111 and SYN112 in the syntax table SYN11 shown in the figure are the same as SYN1001 and SYN1002, respectively, description thereof will be omitted.

  Subsequently, when the CU size is not the minimum (corresponding to “log2CUSize> Log2MinCUSize”) and (SYN113) and cu_split_pred_part_mode is “4” or (SYN114) “5” (SYN115), rem_part_mode [x0] [y0] is decoded (SYN116). In other words, when the CU size is not minimum and the value of cu_split_pred_part_mode is a value corresponding to a horizontally long rectangular PU group or a vertically long rectangular PU group, rem_part_mode [x0] [y0] is decoded. In the above example, the minimum CU is 8 × 8, but is not limited thereto. That is, the minimum CU can be 16 × 16 CU, and the non-minimum CU can be larger than 16 × 16 CU.

  FIG. 16 is a diagram illustrating a configuration example of a syntax table SYN12 at a coding tree level (tree block layer). The syntax table SYN12 is a configuration example when AMP partitioning is prohibited.

  Since SYN 121 and SYN 122 in the syntax table SYN12 shown in FIG. 16 are the same as the above-described SYN 111 and SYN 112, respectively, description thereof will be omitted.

  Subsequently, the CU size is not minimum (SYN123), AMP partitioning is not prohibited (“! Sps_disable_amp_split”) and (SYN124), and cu_split_pred_part_mode is “4” or (SYN125) “5”. If it is found (SYN 126), rem_part_mode [x0] [y0] is decoded (SYN 127). Note that sps_disable_amp_split is a parameter encoded in the SPS as described above.

(Modification)
Below, the preferable modification of the moving image decoding apparatus 1 is demonstrated.

[1] Example of not using joint syntax (joint code) CU partition flag (split_coding_unit_flag), skip flag (skip_flag), merge flag (merge_flag), CU prediction method information (PredMode), and PU partition type information (PartMode) Although the configuration using split_pred_part_mode, which is a syntax that combines information, has been described, the configuration is not limited thereto, and a configuration that does not use such a binding syntax is also possible. For example, it is possible to independently decode a CU partition flag and a skip flag.

  Therefore, in this modification, the join syntax definition table 112 described above is changed to a syntax definition table 112A as shown in FIG.

  It is a structural example of the definition table 112A of syntax (pred_part_mode) defined when the CU size is 16 × 16 or more (in the case of a non-minimum CU).

  The syntax definition table 112A illustrated in FIG. 17 is a table that associates a set of pred_part_mode with PredMode and PartMode. The variable table is applied to pred_part_mode.

  As shown in FIG. 17, in the definition table 112A, the values of pred_part_mode take values of “0”, “1”, “2”, and “3”, and “inter-CUs match CU and PU”, respectively. , “Inter-CU and horizontally long rectangular PU group”, “inter-CU and vertically long rectangular PU group”, and “intra CU”.

  When pred_part_mode is “1 (escape)”, the combined syntax determination unit 111 further specifies “PU_partition type of“ horizontal rectangular PU group in inter CU ””, and further “rem_part_mode”. Is decoded to the combined syntax decoding unit 1011.

  Further, when pred_part_mode is “2 (escape)”, the combined syntax determination unit 111 further specifies “PU_partition type of the vertically long rectangular PU group in the inter CU”, and further includes “rem_part_mode”. "Is instructed to the combined syntax decoding unit 1011 to decode" ".

  Note that the association between rem_part_mode and PartMode is the same as the definition in PU partition type residual information definition table 114A shown in FIG.

  Next, a configuration example of the syntax table in the present modification will be described with reference to FIGS. 18 and 19. FIG. 18 and FIG. 19 are diagrams illustrating a syntax table SYN21 at a coding tree level and a syntax SYN22 at a coding unit level.

  First, the syntax table SYN21 at the coding tree level will be described with reference to FIG.

  As shown in FIG. 18, when the slice type is not an I slice (SYN 211), split_coding_unit_flag is decoded independently (SYN 212).

  Next, the encoding unit level syntax table SYN22 will be described with reference to FIG.

  As shown in FIG. 19, at the coding unit level, first, when the slice type is not an I slice (SYN 221), skip_flag is decoded independently (SYN 222). In the skip mode, a skip process is performed (SYN223).

  When not in skip mode, the following processing is performed. First, when entropy_coding_flag is “1” (SYN224), “pred_type” is decoded (SYN225).

  On the other hand, when entropy_coding_flag is not “1”, pred_part_mode is decoded (SYN226). Further, when the CU size is not minimum and (SYN227) and cu_split_pred_part_mode is “1” or (SYN228) “2” (SYN229), rem_part_mode [x0] [y0] is decoded (SYN230). .

[2] Example in which vertical and horizontal are not distinguished In the above description, the horizontal rectangular PU group and the vertical rectangular PU group are configured as separate groups. However, in the following, a rectangle is included without distinguishing between vertical and horizontal. A configuration example in the case of combining PU partition types will be described. That is, in the modification shown below, non-square PU partition types are handled as one group.

  In the modification shown below, pred_part_mod is used instead of the binding syntax split_pred_part_mode. Pred_part_mode is generally a syntax for specifying PredMode and PartMode. The variable table is applied to pred_part_mode.

[2-1] When using horz_part_flag In the following modification, horz_part_flag that specifies whether a PU partition type belongs to a horizontally long rectangular PU group or a vertically long rectangular PU group is introduced.

  Moreover, in this modification, the above-mentioned pred_part_mode is used. Therefore, in the present modification, the syntax definition table 112 described above is changed to a syntax definition table as shown in FIGS.

  FIG. 20 is a diagram illustrating a configuration example of the syntax definition table 112B1 of pred_part_mode defined when the CU size is 16 × 16 or more (in the case of a non-minimum CU). FIG. 21 is a configuration example of the syntax definition table 112B2 of pred_part_mode defined when the CU size is 8 × 8 (in the case of the minimum CU). The definition tables 112B1 and 112B2 are tables that associate a set of pred_part_mode with PredMode and PartMode.

  First, the definition table 112B1 shown in FIG. 20 will be described. As shown in the figure, in the definition table 112B1, the value of pred_part_mode takes values of “0”, “1”, and “2”, and “PU partition type including square PU in inter CU” and “inter It corresponds to “PU partition type including non-square PU” and “intra CU” in CU. Furthermore, in pred_part_mode “1”, six PU partition types of a horizontally long rectangular PU partition type and a vertically long rectangular PU partition type in inter prediction are grouped.

  When pred_part_mode is “1 (escape)”, “horz_part_flag” and “rem_part_mode” are further specified in order to identify which PU partition type is “PU partition type including non-square PU in inter CU”. Is decrypted.

  When horz_part_flag is “1”, it indicates that the PU partition type belongs to the horizontally long rectangular PU group. Further, when horz_part_flag is “0”, it indicates that the PU partition type belongs to the vertically long rectangular PU group.

  Then, the combined syntax determination unit 111 finally determines the PU partition type based on “rem_part_mode” indicating which PU partition type belongs to the PU group.

  Next, the definition table 112B2 shown in FIG. 21 will be described. As shown in the figure, in the definition table 112B2, the value of pred_part_mode takes values of “0”, “1”, and “2”, and “PU partition type including square PU in inter CU” and “inter It corresponds to “PU partition type including non-square PU” and “intra CU” in CU. This is the same as the definition table 112B1 shown in FIG. 20, but differs in the following.

  That is, in the definition table 112B2, escape is specified both when pred_part_mode is “1” and when it is “2”.

  When pred_part_mode is “1”, “horz_part_flag” is further decoded in order to specify “PU partition type including non-square PU in inter CU”, that is, whether the PU partition type is horizontal or vertical. . When “horz_part_flag” is “1”, the PU partition type is 2N × N of a horizontally long rectangle. When “horz_part_flag” is “0”, the vertical rectangular PU partition type is N × 2N.

  When pred_part_mode is “2”, “rem_part_mode” is further decoded in order to specify which 2N × 2N or N × N PU partition type of “Intra CU”. When “rem_part_mode” is “0”, the PU partition type is 2N × 2N. When “rem_part_mode” is “1”, the PU partition type is N × N.

  Next, a configuration example of the syntax table in this modification will be described with reference to FIG. FIG. 22 is a diagram showing a syntax table SYN31 at the coding tree level.

  As shown in FIG. 22, SYN 311 to SYN 316 are the same as SYN 221 to SYN 226 in the syntax table shown using FIG.

  Subsequently, when pred_part_mode is “1” (SYN 317), horz_part_flag is further decoded (SYN 318). Here, if the CU size is not minimum (SYN 319), rem_part_mode is decoded (SYN 320).

(Action / Effect)
As described above, a PU group is defined as a union of a set of horizontally long rectangular PU partition types and a set of vertically long rectangular PU partition types.

  In a region where the texture is complex, there is a property that non-square PU partition types occur continuously. For this reason, according to the above configuration, in a situation where non-square PU partition types occur continuously, a variable table so that a shorter code is decoded for each non-square PU partition type belonging to the PU group. Since adaptive processing is performed, the amount of codes can be reduced.

  Note that the definition table 112B1 illustrated in FIG. 20 has a configuration in which vertical and horizontal rectangles are distinguished using horz_part_flag, but a configuration in which horz_part_flag is not used as illustrated below with reference to FIG.

  FIG. 23 shows a definition table 112B1 'which is another configuration example of the definition table 112B1 of the syntax (pred_part_mode) defined when the CU size is 16 × 16 or more (in the case of a non-minimum CU).

  As shown in FIG. 23, in the definition table 112B1 ′, the values of pred_part_mode take values of “0”, “1”, and “2”, and “PU partition type including square PU in inter CU”, “ It corresponds to “PU partition type including non-square PU in inter CU” and “intra CU”. The difference between the definition table 112B1 'and the definition table 112B1 is that in the definition table 112B1', the value of rem_part_mode is assigned to the six PU partition types of non-square PUs without distinguishing vertical and horizontal rectangles.

  In the example shown in FIG. 23, “PART — 2N × N”, “PART — 2N × nU”, and “PART — 2N × nD” are assigned to “0”, “2”, and “4”, respectively. Yes. Further, “PART_N × 2N”, “PART_nL × 2N”, and “PART_nR × 2N” of the vertically long rectangular PU division type are assigned to “1”, “3”, and “5”, respectively. In addition, by predetermining the relationship between the pred_part_mode value and the PU partition type value as described above, the same PU partition type is the same when the CU size is 16 × 16 or larger and when it is 8 × 8. There is an advantage that the value of pred_part_mode is associated.

[2-2] Further, in the case of using the coupling syntax (joint code) In the modification [2-1], the configuration using pred_part_mode has been described. Below, the structure which uses cu_split_pred_part_mode instead of pred_part_mode is demonstrated.

  Therefore, in this modification, the syntax definition tables 112B1 and 112B2 described above are changed to the definition table of the combined syntax as shown in FIGS.

  FIG. 24 is a diagram illustrating a configuration example of the combined syntax definition table 112B3 of cu_split_pred_part_mode defined when the CU size is 16 × 16 or more (in the case of a non-minimum CU). FIG. 25 is a configuration example of the combined syntax definition table 112B4 of cu_split_pred_part_mode defined for the case where the CU size is 8 × 8 (in the case of the minimum CU).

  First, the combined syntax definition table 112B3 shown in FIG. 24 will be described. As shown in the figure, in the combined syntax definition table 112B3, the value of cu_split_pred_part_mode takes a value of “0” to “5”.

  “0” corresponds to CU partitioning, and “1” corresponds to skip mode. “2” corresponds to inter 2N × 2N to be merged.

  “3”, “4”, and “5” correspond to “PU partition type including square PU in inter CU”, “PU partition type including non-square PU in inter CU” and “intra CU”, respectively. To do.

  The definitions of “3”, “4”, and “5” are substantially the same as “0”, “1”, and “2” in the definition table 112B1 shown using FIG. Is omitted.

  In “4”, “escape” is specified, and the combined syntax determination unit 111 uses FIG. 20 to instruct the combined syntax decoding unit 1011 to further decode “horz_part_flag” and “rem_part_mode”. This is the same as “1” in the definition table 112B1 shown in FIG.

  Next, the combined syntax definition table 112B4 shown in FIG. 25 will be described. As shown in the figure, in the combined syntax definition table 112B4, the values of pred_part_mode take values of “0”, “1”, “2”, “3”, and “4”, respectively, This corresponds to “skip mode”, “inter 2N × 2N performing merge”, “PU partition type including square PU in inter CU”, “PU partition type including non-square PU in inter CU”, and “intra CU”.

  Note that the definitions of “2”, “3”, and “4” are substantially the same as “0”, “1”, and “2” in the definition table 112B2 shown using FIG. The description is omitted.

[2-2-1] Furthermore, in the case where the definition table of the combined syntax is made common In the above modification 2-2, the CU size is 16 × 16 or more, and the CU size is 8 × 8 (minimum CU size). ), A configuration for setting a definition table having a different combination syntax (cu_split_pred_part_mode) is shown. Hereinafter, a configuration for sharing a definition table will be described with reference to FIG.

  First, a description will be given of the definition table 112B6 of the combined syntax (cu_split_pred_part_mode) shown in FIG. 39 that can be used in common when the CU size is 16 × 16 or more and when the CU size is 8 × 8. As shown in the figure, in the combined syntax definition table 112B6, the value of cu_split_pred_part_mode takes a value of “0” to “5”.

  The definition of “0” to “4” is substantially the same as the definition of each corresponding value in the definition table 112B3 shown with reference to FIG. When the value of cu_split_pred_part_mode is “4”, “escape” is specified, and the combined syntax determination unit 111 uses “horz_part_flag” and “rem_part_mode” together to set the final PU partition type (PartMode) value. decide. The value of horz_part_flag is set regardless of the CU size. On the other hand, the value of rem_part_mode is set to a decoded value when the CU size is 16 × 16 or more, but when the CU size is 8 × 8, the default value “0” is set. The

  Here, the definition of “5” will be described as follows. When the value of cu_split_pred_part_mode is “5”, “escape” is specified, and the combined syntax determination unit 111 determines the final PU partition type value together with the value of “rem_part_mode”. The value of rem_part_mode is set to a decoded value when the CU size is 8 × 8, but a default value of “0” is set when the CU size is 16 × 16 or more. The

  The definition table 112B6 includes the definition of the correspondence between the syntax value of cu_split_pred_part_mode and the CU partition flag regardless of the CU size. However, since the CU partitioning is not applied in the minimum CU size (CU size 8 × 8), the value range of cu_split_pred_part_mode is 1 to 5 for a CU having the minimum CU size and 0 to 5 for a CU having a non-minimum CU size. In the variable table, it is preferable that the code number of 0 to 4 and the syntax value of cu_split_pred_part_mode of 1 to 5 are associated on a one-to-one basis with the minimum CU size so that the value of cu_split_pred_part_mode becomes the value in the range. In the non-minimum CU size, it is preferable that the code numbers 0 to 5 and the syntax values 0 to 5 of cu_split_pred_part_mode are associated one-to-one.

  The initialization of the variable table applied when realizing the association between the code number (codeNum) in the variable table as described above and the syntax value of cu_split_pred_part_mode will be described with reference to FIG. . FIG. 40 shows an example of a variable table initialization table applied when realizing the code value (codeNum) and the syntax value of cu_split_pred_part_mode in the variable table as described above. In the initialization of the variable table based on FIG. 40, when the CU division depth (cuDepth) is 0 to 2, that is, in the case of the non-minimum CU size, the variable table elements corresponding to the code numbers 0 to 5 are Set to the same syntax value as the number. When cuDepth is 3, that is, when the CU size is the minimum, the variable table element corresponding to each of code numbers 0 to 4 is set to a value obtained by adding 1 to the code number. The initialization of the variable table based on FIG. 40 can also be expressed as follows when the variable table element corresponding to the code number codeNum is indicated as decTable [codeNum].

decTable [codeNum] = codeNum (when CU size is non-minimum CU size)
decTable [codeNum] = codeNum + 1 (when the CU size is the minimum CU size)
[2-3] Further, in the case of prohibiting AMP In the above, the configuration using AMP has been described. However, in the following modification, in the configuration in which vertical and horizontal are not distinguished using FIG. The configuration of will be described. FIG. 26 is a diagram illustrating a configuration example of the definition table 112B5 of the syntax (pred_part_mode) defined when the CU size is 16 × 16 or more (in the case of a non-minimum CU). Also in this modification, the above-described horz_part_flag is introduced.

  As shown in FIG. 26, in the definition table 112B5, the values of pred_part_mode take values of “0”, “1”, and “2”, respectively, and “PU partition type including square PU in inter CU” and “inter It corresponds to “PU partition type including non-square PU” and “intra CU” in CU. This is the same as the definition table 112B1 shown in FIG. 20, but differs in the following.

  That is, in the definition table 112B5, when pred_part_mode in which escape is specified is “1”, an asymmetric PU related to AMP is not defined. Therefore, similarly to the definition table 112B2 illustrated in FIG. 21, the PU partition type is set according to “horz_part_flag”. Identified. That is, in this modification, the combined syntax determination unit 111 and the combined syntax decoding unit 1011 do not have to decode rem_part_mode.

  In the case where the CU size is 8 × 8 (in the case of the minimum CU), the definition table 112B2 shown in FIG. 21 can be used, and the description thereof is omitted here.

[2-4] Further, when CABAC is used In the above, the configuration using CAVLC has been described. However, in the following modification, a configuration using CABAC in a configuration that does not distinguish between vertical and horizontal will be described with reference to FIG. To do.

  In order to group rectangular PUs without distinguishing vertical rectangles and horizontal rectangles when using CABAC, the PU partition type (pred_type) information is binary-coded on the video encoding device 2 side using the binary setting method TBL11 shown in FIG. In other words, on the moving picture decoding apparatus 1 side, the combined syntax decoding unit 1011 may use an independent context for decoding binary corresponding to the position indicated by square_flag in FIG. In other words, the probability table used in the binary arithmetic decoding may be independently set and updated.

  The binary setting method TBL11 shown in FIG. 27 defines a case where CU> 8 × 8 and a case where CU == 8 × 8.

  In the case of CU> 8 × 8, intra_flag, square_flag, horz_part_flag, and rem_part_mode are binarized. intra_flag, square_flag, and horz_part_flag are binarized by 1 bit, and rem_part_mode is binarized by 1 or 2 bits. In the figure, “-” indicates that the parameter is not binarized. Further, horz_part_flag indicates whether it is a horizontally long rectangular PU partition type or a vertically long rectangular PU partition type.

  The binary at the position of square_flag is information indicating that the target CU is an inter 2N × 2N PU partition type (square PU partition type) or other inter PU partition types (non-square PU partition type). In the example shown in FIG. 27, square_flag is binarized at the second bit of the binary string.

  For example, in the case of an inter PU partition type, when a 2N × 2N PU partition type is binarized, “1” is binarized as square_flag. For other PU partition types, “0” is binarized as square_flag.

  The joint syntax decoding unit 1011 performs arithmetic decoding using an independent context for the binary, thereby improving the coding efficiency in a situation where the rectangular PUs are continuous.

  In FIG. 27, for convenience of explanation, the name square_flag is assigned to the binary position of the second bit, and an independent context is set at this binary position, but this is not restrictive.

  That is, (1) information indicating whether a binary when pred_type is binarized is a PU partition type is rectangular (non-square) or other (square), and (2) context independent of the binary It is possible to improve the coding efficiency by performing the arithmetic coding by setting.

[3] Use of Inter 2N × 2N Flag PU partition type information can also be expressed by a combination with a syntax different from the syntax described above. In the following modification, a configuration in which the PU partition type is expressed by combining the above-described pred_part_mode and the inter 2N × 2N flag will be described. The inter 2N × 2N flag is a flag indicating whether or not the inter 2N × 2N is applied.

  In this modification, the definition table 112 of the combined syntax described above is changed to a syntax definition table as shown in FIG. The variable table is applied to pred_part_mode. In addition, a code shorter than a code assigned to a PU partition type other than the inter 2N × 2N is assigned to the inter 2N × 2N flag.

  FIG. 28 shows a configuration example of a syntax definition table 112C regarding a set of an inter 2N × 2N flag (inter 2N × 2N flag) and pred_part_mode defined when the CU size is 16 × 16 or more (in the case of a non-minimum CU) FIG.

  In this modification, first, if the PU partition type is inter 2N × 2N, the PU partition type is specified by the inter 2N × 2N flag.

  When PredMode · PartMode is not inter 2N × 2N, pred_part_mode is associated with PredMode and PartMode.

  That is, as shown in FIG. 28, in the definition table 112C, the values of pred_part_mode take values of “0”, “1”, and “2”, and “inter-CU is a horizontally long rectangular PU group” and “inter-CU”, respectively. Corresponds to “vertically long rectangular PU group” and “intra CU”.

  When pred_part_mode is “0 (escape)”, the combined syntax determination unit 111 further sets “rem_part_mode” in order to identify which PU partition type of the “inter-CU horizontally long rectangular PU group”. Instructs the combined syntax decoding unit 1011 to perform decoding.

  In addition, when pred_part_mode is “1 (escape)”, the combined syntax determination unit 111 further specifies “PU_partition type of the vertically long rectangular PU group in the inter CU”, in order to further specify “rem_part_mode” "Is instructed to the combined syntax decoding unit 1011 to decode" ".

  Note that the association between rem_part_mode and PartMode is the same as the definition in PU partition type residual information definition table 114A shown in FIG.

  Next, a configuration example of the syntax table in this modification will be described with reference to FIG. FIG. 29 is a diagram showing a syntax table SYN41 of the coding unit level.

  Since SYN 411 to SYN 415 of the syntax table SYN 41 shown in FIG. 29 are the same as SYN 221 to SYN 225 of FIG. 19, their descriptions are omitted.

  When entropy_coding_flag is not “1”, processing is performed as follows. First, inter_2Nx2N_flag (SYN416) and pred_part_mode (SYN417) are decoded.

  Subsequently, when the CU size is not minimum and (SYN418) and cu_split_pred_part_mode is “0” or (SYN419) “1” (SYN420), rem_part_mode [x0] [y0] is decoded (SYN421). ).

(Action / Effect)
Inter 2N × 2N PU partition types tend to have higher probability of occurrence than other PU partition types.

  According to the above modification, a code shorter than other PU partition types is assigned to inter 2N × 2N having a high occurrence probability among PU partition types. Also, the inter 2N × 2N is excluded from the variable table adaptive processing target.

  Since the variable table adaptation process is applied to the other PU partition types “inter-CU horizontally long rectangular PU group”, “inter-CU vertically long rectangular PU group”, and “intra CU”, the past decoding history For these PU partition types, codes longer than inter 2N × 2N and shorter codes are assigned to PU partition types with a high probability of occurrence.

  As described above, by independently decoding the flag indicating whether or not inter 2N × 2N is applied, a short code can always be assigned to inter 2N × 2N regardless of the state of the variable table. As a result, the code amount can be reduced.

  Note that this modification can also be applied to the case of using the combined syntax cu_split_pred_part_mode instead of pred_part_mode.

[4] Modified Example of Variable Table Adaptation Processing In the above description, the variable table adaptation processing is performed on the horizontally long rectangular PU group and the vertically long rectangular PU group. In the above description, for example, one syntax value is assigned to the horizontally long rectangular PU group, and the variable table is applied to the syntax. In this configuration, when one of the horizontally long rectangular PU partition types is selected, the variable table adaptive process is performed so that a short code is assigned to the other horizontally long rectangular PU partition types.

  However, the present invention is not limited to this, and a configuration in which a horizontally long rectangular PU group and a vertically long rectangular PU group are not used is also possible.

  In the following modification, the moving picture decoding apparatus 1 described above is changed as follows.

  (1) An independent syntax value is assigned to each PU partition type belonging to the horizontally long rectangular PU group and to each PU partition type belonging to the vertically long rectangular PU group. For example, the combined syntax definition table 112 is changed to a table in which an independent syntax value is assigned to each PU partition type belonging to the horizontally long rectangular PU group and each PU partition type belonging to the vertically long rectangular PU group. The variable table is applied to the independent syntax value (hereinafter referred to as variable table 1012E).

  (2) Variable table adaptation processing is performed for PU partition types belonging to the same PU group. For example, when the variable table adaptation unit 1015 selects a PU partition type belonging to a horizontally long rectangular PU group in the adaptation process of the variable table 1012E, the variable table adaptation unit 1015 performs swap processing in the variable table so that the code assigned to the PU partition type is shortened. At the same time, the variable table is changed so that the code assigned to the PU partition type belonging to the same group is also shortened.

  This will be specifically described with reference to FIG. FIG. 30 is a diagram illustrating an example of variable table adaptation processing when independent syntax values are assigned to each PU partition type belonging to a horizontally long rectangular PU group and to each PU partition type belonging to a vertically long rectangular PU group.

  A state ST11 illustrated in FIG. 30 illustrates an initial state of the variable table 1012E. In the variable table 1012E, for the code numbers “0” to “6”, syntax values “2N × 2N”, “2N × N”, “N × 2N”, “2N × nU” of the PU division type are respectively provided. ”,“ 2N × nD ”,“ nL × 2N ”, and“ nR × 2N ”.

  Here, when the code number “2” associated with “N × 2N” is decoded, the variable table adaptation unit 1015 selects the same PU group as “N × 2N” in the variable table 1012E. Transition to state ST12. The shaded portion of the variable table 1012E is a PU partition type belonging to the same vertically long rectangular PU group as N × 2N.

  In the state ST12, in the variable table 1012E, “nL × 2N” and “nR × 2N” belonging to the same vertical rectangular PU group as “N × 2N” correspond to the code numbers “5” and “6”, respectively. It is attached.

  Furthermore, the variable table adaptation unit 1015 updates the variable table 1012E so that a short code is assigned to each selected PU partition type. Specifically, the variable table adaptation unit 1015 performs swap for the PU partition types selected in order from the smallest code number as indicated by an arrow in the state 12. Transition to state ST13.

  In state ST13, “N × 2N” associated with code number “2” is swapped with “2N × N” associated with code number “1” by the variable table adaptation processing. . That is, “N × 2N” is associated with the code number “1”. Similarly, “nL × 2N” and “nR × 2N” are associated with the code numbers “4” and “5” by swapping, respectively.

[5] Application of CABAC In the configuration described above, the CAVLC decoding method is used in the configuration that distinguishes the vertical and horizontal directions. However, arithmetic coding (CABAC) may be applied in a configuration in which vertical and horizontal are distinguished.

  For example, although it has been described that the code number is decoded based on the VLC table, a binary string (bin) corresponding to the code number is defined based on the VLC table, and then the binary string is decoded using arithmetic coding. May be.

  In addition, a process corresponding to the variable table adaptation process can be realized by a CABAC mechanism. That is, “when a PU partition type belonging to a horizontally long rectangular PU group is decoded, shortening a code assigned to another PU partition type belonging to a horizontally long rectangular PU group” means that a CABAC mechanism is used instead of a variable table. Can be realized. The same applies to the vertically long rectangular PU group.

  Specifically, the combined syntax decoding unit 1011 may perform arithmetic decoding by CABAC as follows. That is, the combined syntax decoding unit 1011 interprets that a certain binary (1 bit) is assigned as information on whether horizontal rectangular PU partitioning or vertical rectangular PU partitioning is used, and a context independent of the binary. Should be set.

  For example, a binary string can be configured as defined in the table TBL21 shown in FIG. FIG. 31 is a diagram illustrating a configuration example of a binary string to be arithmetically encoded.

  As shown in FIG. 31, in the table TBL21, a binary of horz_part_flag is set as information as to whether horizontal rectangular PU partitioning or vertical rectangular PU partitioning is used.

  When horz_part_flag is “1”, it indicates that horizontal rectangular PU partitioning is used, and when it is “0”, it indicates that vertical rectangular PU partitioning is used.

  Moreover, the joint syntax decoding part 1011 can set an independent context to horz_part_flag, and can perform arithmetic decoding based on the table TBL21.

[6] Variable Table Adaptation Using Counter The variable table adaptation unit 1015 may perform swap using the counter shown in FIG. 32 or the differential counter shown in FIG.

  First, the configuration of the variable table 1012F with the number counter (counter) 355 and the sum counter (counter) 356 will be described with reference to FIG. FIG. 32 is a diagram showing the variable table 1012F with the number counter 355 and the sum counter 356.

The variable table 1012F is a table in which the code number codeNum and the table index s _x are associated with each other. In FIG. 32, table indexes s _{0 to} s ₄ are associated with rank = ₀ to rank = 4. Note that rank = 5 and later are omitted.

The number counter 355 is a counter table for counting the number of occurrences of the code numbers codeNum = 0, 1, and 2. As shown in FIG. 32, the number counter 355 is provided with counters c ₀ , c ₁ , and c ₂ for code numbers codeNum = 0, 1, and 2, respectively. The number counter 355 is preferably set only to a small rank such as code numbers codeNum = 0, 1, and 2.

  The sum counter 356 is a counter that holds the sum of the values of the counters included in the number counter 355. In FIG. 32, the value held by the sum counter 356 is expressed as sum.

The variable table adaptation unit 1015 counts the number of times of the decoded code number codeNum and reflects it in the value of the counter corresponding to the code number codeNum. Further, by counting up when the value of the counter of the counter c _n of the counter number n was the counter number n-1 counter c _n-1 value or more, the variable table adaptation unit 1015, the table index s _n and _{s n-1} as well as swapping, swap the values of and _{c n-1} of the counter _{c n.}

When the code number codeNum ≧ 2, the table indexes s _rank-1 and s _rank may be swapped.

  When the total value sum of the values of the counters reaches a predetermined value (for example, 15), the variable table adaptation unit 1015 resets the counter. This process is called normalization. Normalization is performed for the purpose of suppressing an excessive increase in the counter value.

  As described above, in the variable table adaptation processing when the variable table 1012F with the number counter 355 and the sum counter 356 is used, the table index stored in the variable table 1012F is swapped under a predetermined condition. Further, normalization is performed at every predetermined count to suppress an excessive increase in the counter value.

  Next, the configuration of the variable table 1012G with the difference value counter (counter) 354 will be described with reference to FIG. FIG. 33 is a diagram showing the variable table 1012G with the difference value counter 354.

  The difference value counter 354 is a counter that holds a difference approximate value between the number of occurrences of a certain code number codeNum and the number of occurrences of a code number codeNum-1 smaller than the certain code number.

As shown in FIG. 33, the difference value counter 354 includes a difference value counter c ′ ₁ that holds a difference approximation value between the number of occurrences of code number codeNum = 0 and the number of occurrences of cn = ₁ , and code number codeNum = A difference value counter c ′ ₂ that holds a difference approximate value between the number of occurrences of 1 and the number of occurrences of rank = ₂ is provided. Hereinafter, the difference value counter c ′ ₁ is also referred to as a difference value counter corresponding to the code number codeNum = 1. The difference value counter c ′ ₂ is also referred to as a difference value counter corresponding to the code number codeNum = 2.

  Note that the value of the difference value counter is reset at a prescribed timing (for example, when decoding of a picture is started or when decoding of a slice is started). The resetting of the differential value counters sets all differential value counter values to 0. The value of the difference value counter may be set to a value other than 0 by resetting the difference value counter.

Variable table adaptation unit 1015 is a when the code number codeNum = 1 is decoded, 'not equal the value of ₁ is 0, the difference value counter c' difference value counter c with 1 reduces the value of _1, the difference value The value of the counter c ′ ₂ is incremented by 1.

Further, the variable table adaptation unit 1015 increases the value of the difference value counter c ′ ₂ by 1 when the code number codeNum = 1 is decoded and the value of the difference value counter c ′ ₁ is 0. , Swap table indexes s ₀ and s ₁ .

The variable table adaptation unit 1015, effected even if the code number codeNum = 2 is decoded, and 'not equal ₂ 0, the difference value counter c' difference value counter c to 1 decreases the value of _2.

The variable table adaptation unit 1015 swaps the table indexes s ₁ and s ₂ when the code number codeNum = 2 is decoded and the difference value counter c ′ ₂ is 0.

When the code number codeNum ≧ 3, the variable table adaptation unit 1015 may swap the table indexes s _rank−1 and s _rank .

[7] Example of grouping PU partition types having the same number of partitions In the following, a configuration example in which PU partition types having the same number of partitions are handled as one group will be described.

  In this modification, the definition table 112B3 (FIG. 24) of the combined syntax applied to the non-minimum CU size described in the modification of [2-2] is changed to the syntax definition table 112B7 shown in FIG. Further, the definition table 112B4 (FIG. 25) of the combined syntax applied to the minimum CU size described in the modification example [2-2] is changed to the syntax definition table 112B8 shown in FIG.

  First, the definition table 112B7 of the combined syntax applied to the non-minimum CU size will be described with reference to FIG. FIG. 41 is a diagram illustrating a configuration example of the syntax definition table 112B7 related to cu_split_pred_part_mode defined when the CU size is 16 × 16 or more (in the case of a non-minimum CU).

  In the definition table 112B7, the value of cu_split_pred_part_mode takes a value from “0” to “4”. A value of “3” corresponds to “PU partition type group with 1 partition in the CU”, and a value of “4” corresponds to “PU partition type group with 2 partitions in the CU”. The definition of each value of “0” to “2” is the same as that of the definition table 112B3 and is omitted.

  When cu_split_pred_part_mode is “3”, the combined syntax determination unit 111 further specifies “PU_partition_mode_PU_partition_number_PU_partition_type_PU_partition_type”. "Is instructed to the combined syntax decoding unit 1011 to decode" ". In this case, if the value of rem_part_mode is 0, it indicates that PredMode is MODE_INTER. If the value of rem_part_mode is 1, the value of PredMode is set to MODE_INTRA. The value of PartMode is set to Part_2Nx2N.

  When cu_split_pred_part_mode is “4”, the combined syntax determination unit 111 further specifies “PUz partition type of which the number of partitions in the CU is 2”, and further specifies “horz_part_flag. "And" rem_part_mode "are instructed to the combined syntax decoding unit 1011 to decode. In this case, the association between rem_part_mode and PartMode is the same as the definition in the PU partition type residual information definition table 114A shown in FIG.

  Next, the definition table 112B8 of the combined syntax applied to the minimum CU size will be described using FIG. FIG. 42 is a diagram illustrating a configuration example of the syntax definition table 112B8 related to cu_split_pred_part_mode defined when the CU size is 8 × 8 (in the case of the minimum CU).

  In the definition table 112B8, the value of cu_split_pred_part_mode takes a value from “0” to “4”. A value of “2” corresponds to “PU partition type group with 1 partition in the CU”, and a value of “3” corresponds to “PU partition type group with 2 partitions in the CU”. The value of “4” corresponds to “PU partition type group with 4 partitions in the CU”. The definition of the values “0” and “1” is the same as the definition table 112B4 in FIG.

  When the value of cu_split_pred_part_mode is “2” and “3”, the description is omitted in the definition table 112B7 of FIG. 41 described above, which is the same as when cu_split_pred_part_mode is “3” and “4”, respectively. However, since the asymmetric partition is not applied to the minimum CU size, it is not necessary to decode the information of rem_part_mode when “the number of partitions in the CU is two”.

  When cu_split_pred_part_mode is “4”, this indicates “PU partition type with 4 partitions in CU”. In this modification, the number of partitions is 4 when the intra partition with PU partition type is Part_NxN. Since there are only CUs, the corresponding values are set as PredMode and PartMode values.

(Action / Effect)
In general, a complex area tends to be divided into a large number of partitions, and therefore, a division type including a large number of partitions in a CU is easily selected. Since the complexity of a region changes locally, there is a tendency that division types having the same number of divisions are easily selected continuously for a specific region. Therefore, by setting the same division number, that is, the division type having the same number of partitions in the CU, to the group with another PU division type for the PU division type with an appropriate division number according to the complexity of the region. Since a shorter code can be assigned, the amount of codes can be reduced.
[8] Examples of different connection syntax In the above modification [2], PU partition types including rectangles are grouped without distinguishing between vertical and horizontal, and the syntax used for decoding of the PU partition type is as follows. A configuration example in the case of using the binding syntax has been described. The combination syntax in the modified example [2] is an index that specifies a combination of a CU partition flag, a skip flag, a merge flag, CU prediction method information, and PU partition type information. (Syntax) may be used.

[8-1] When the join syntax is an index that specifies a combination of a CU partition flag, a skip flag, CU prediction method information, and PU partition type information (when the join syntax does not include information related to the merge flag) )
Hereinafter, details of a modified example (modified example [8-1]) in the case of using the above-described coupling syntax will be described with reference to the drawings.

  In this modification, the definition table 112B3 (FIG. 24) of the combined syntax applied to the non-minimum CU size described in the modification of [2-2] is changed to the syntax definition table 112B9 shown in FIG. Also, the combined syntax definition table 112B4 (FIG. 25) applied to the minimum CU size described in the modification of [2-2] is changed to the syntax definition table 112B10 shown in FIG. The details of each definition table are as follows.

  FIG. 43 is a configuration example of the definition table 112B9 of the syntax (cu_split_pred_part_mode) defined when the CU size is 16 × 16 or more (in the case of a non-minimum CU).

  The syntax definition table 112B9 illustrated in FIG. 43 is a table that associates a set of syntax values cu_split_pred_part_mode, horz_part_flag, rem_part_mode, and intra_part_mode with a set of variable values split_coding_unit_flag, skip_flag, PredMode, and PartMode. The variable table is applied to cu_split_pred_part_mode.

  As shown in FIG. 43, in the definition table 112B9, the value of cu_split_pred_part_mode takes the values “0”, “1”, “2”, “3”, and “4”, and each is divided into “small CUs”. It corresponds to “CU”, “skip CU”, “CU that is an inter CU and the PU size is equal to the CU size”, “rectangular PU group with inter CU”, and “intra CU”.

  When cu_split_pred_part_mode is “3 (escape)”, the combined syntax determination unit 111 further specifies “horz_part_flag” in order to identify which PU partition type of the “inter-CU and rectangular PU group”. Instructs the combined syntax decoding unit 1011 to decode “rem_part_mode”.

  The association between the horz_part_flag and rem_part_mode and the PartMode is the same as that in the modification [2-1], and thus the description thereof is omitted here.

  FIG. 44 is a configuration example of the definition table 112B10 of the syntax (cu_split_pred_part_mode) defined when the CU size is 8 × 8 (in the case of the minimum CU).

  The syntax definition table 112B10 illustrated in FIG. 44 is a table that associates a set of syntax values cu_split_pred_part_mode, horz_part_flag, rem_part_mode, and intra_part_mode with a set of variable values split_coding_unit_flag, skip_flag, PredMode, and PartMode. The variable table is applied to cu_split_pred_part_mode.

  As shown in FIG. 44, in the definition table 112B10, the value of cu_split_pred_part_mode takes the values “1”, “2”, “3”, and “4”. The meaning of each value is the same as the value of cu_split_pred_part_mode in the syntax definition table 112B9 described with reference to FIG.

  When cu_split_rped_part_mode is “3 (escape)”, the combined syntax determination unit 111 further sets “horz_part_flag” in order to identify which PU partition type of the “inter-CU and rectangular PU group”. Instructs the combined syntax decoding unit 1011 to perform decoding. The combined syntax determination unit 111 sets the PU partition type (PartMode) to PART_Nx2N when the value of horz_part_flag is “0”, and to PART_2NxN when the value of horz_part_flag is “1”.

  When cu_split_pred_part_mode is “4 (escape)”, the combined syntax determination unit 111 further decodes “intra_part_mode” in order to identify which PU partition type is “intra CU”. Instructs the combined syntax decoding unit 1011. The join syntax determination unit 111 sets the PU partition type (PartMode) to PART_2Nx2N if the value of intra_part_mode is “0”, and sets it to PART_NxN if the value is 1.

  Furthermore, in the present modification, SYN 51 shown in FIG. 45 is used as the syntax of the encoding unit level. A configuration example of the syntax table in this modification will be described with reference to FIG. FIG. 45 is a diagram illustrating a syntax SYN51 of a coding unit level.

  As shown in FIG. 45, when the slice type is not an I slice and entropy_coding_mode_flag is “1” (SYN511), skip_flag is decoded independently (SYN512). In the skip mode, skip processing is performed (SYN 513).

  When not in skip mode, the following processing is performed. First, when entropy_coding_mode_flag is “1” (SYN 514), “pred_type” is decoded (SYN 515).

  On the other hand, when entropy_coding_flag is not “1”, the following processing is performed. First, when slice_type is “I” (target slice is I_Slice) or the value of cu_split_pred_part_mode is “4” (SYN516) and the target CU size is the smallest, “intra_part_mode” is decoded (SYN517). ).

  Next, when slice_type is not “I” (target slice is I_Slice) and the value of cu_split_pred_part_mode is “3” (SYN 518), horz_part_flag is decoded (SYN 519). Furthermore, when the CU size is not the minimum, rem_part_mode [x0] [y0] is decoded (SYN520).

(Action / Effect)
According to the configuration of the modified example [8-1] above, the non-square PU is also used when the combined syntax specifies a combination of the CU partition flag, the skip flag, the CU prediction method information, and the PU partition type information. In a situation where division types occur continuously, variable table adaptation processing is performed so that a shorter code is decoded for each non-square PU division type belonging to the PU group, thereby reducing the amount of codes. be able to. In other words, the above code amount reduction effect can be obtained even when the combined syntax does not include information related to the merge flag.

[8-2] When the combined syntax is an index specifying a combination of a merge flag, a skip flag, CU prediction method information, and PU partition type information (when the combined syntax does not include information on a CU partition flag) )
Hereinafter, details of a modified example (modified example [8-2]) in the case of using the above-described coupling syntax will be described with reference to the drawings.

  In this modification, the combined syntax definition table 112B10 (FIG. 43) applied to the non-minimum CU size described in the modification of [8-1] is changed to the syntax definition table 112B11 shown in FIG. Also, the definition table 112B10 (FIG. 44) of the combined syntax applied to the minimum CU size described in the modification of [8-1] is changed to the syntax definition table 112B12 shown in FIG. The details of each definition table are as follows.

  FIG. 46 is a configuration example of the definition table 112B11 of the syntax (cupred_part_mode) defined when the CU size is 16 × 16 or more (in the case of a non-minimum CU).

  The syntax definition table 112B11 illustrated in FIG. 46 is a table that associates a set of syntax values cu_pred_part_mode, horz_part_flag, rem_part_mode, and intra_part_mode with a set of variable values merge_flag, skip_flag, PredMode, and PartMode. The variable table is applied to cu_pred_part_mode. Further, the value of the CU partitioning flag (split_coding_unit_flag) is decoded independently of the combined syntax cu_pred_part_mode.

  As shown in FIG. 46, in the definition table 112B11, the value of cu_pred_part_mode takes values of “0”, “1”, “2”, “3”, and “4”, and “skip CU” and “merge”, respectively. It corresponds to “CU”, “CU that is an inter CU and the PU size is equal to the CU size”, “rectangular PU group with inter CU”, and “intra CU”.

  When cu_pred_part_mode is “3 (escape)”, the combined syntax determination unit 111 further specifies “horz_part_flag” in order to identify which PU partition type is “inter-CU and rectangular PU group”. Instructs the combined syntax decoding unit 1011 to decode “rem_part_mode”.

  The association between the horz_part_flag and rem_part_mode and the PartMode is the same as that in the modification [2-1], and thus the description thereof is omitted here.

  FIG. 47 is a configuration example of the definition table 112B12 of the syntax (cu_pred_part_mode) defined when the CU size is 8 × 8 (in the case of the minimum CU).

  The syntax definition table 112B12 illustrated in FIG. 47 is a table that associates a set of syntax values cu_pred_part_mode, horz_part_flag, rem_part_mode, and intra_part_mode with a set of variable values skip_flag, merge_flag, PredMode, and PartMode. The variable table is applied to cu_pred_part_mode.

  As shown in FIG. 47, in the definition table 112B12, the value of cu_pred_part_mode takes values “0”, “1”, “2”, “3”, and “4”. The meaning of each value is the same as the value of cu_pred_part_mode in the syntax definition table 112B11 described with reference to FIG.

  When cu pred_part_mode is “3 (escape)”, the combined syntax determining unit 111 further specifies “PUz type of inter-CU and rectangular PU group”, and further specifies “horz_part_flag”. Is decoded to the combined syntax decoding unit 1011. Note that the association between horz_part_flag and PartMode is the same as in the modification [8-1], and a description thereof is omitted.

  When cu pred_part_mode is “4 (escape)”, the combined syntax determination unit 111 further decodes “intra_part_mode” in order to identify which PU partition type is “intra CU”. To the combined syntax decoding unit 1011. Note that the association between intra_part_mode and PartMode is the same as in the modification [8-1], and a description thereof will be omitted.

  As the syntax of the coding unit level used in the present modification, the syntax obtained by replacing the combined syntax cu_split_pred_part_mode with the combined syntax cu_pred_part_mode in the SYN 51 shown in FIG. 45 described in the modified example [8-1] can be used.

(Action / Effect)
According to the configuration of the modified example [8-2] above, even when the join syntax is an index that specifies a combination of the merge flag, the skip flag, the CU prediction method information, and the PU partition type information, In situations where PU partition types occur continuously, variable table adaptation processing is performed so that shorter codes are decoded for each of the non-square PU partition types belonging to the PU group. Can be planned. In other words, the above code amount reduction effect can be obtained even when the combined syntax does not include information related to the CU partition flag.

[9] Example of grouping asymmetric partitions Hereinafter, a configuration example in the case where PU partition types classified as asymmetric partitions are handled as one group will be described.

  In this modification, the definition table 112B3 (FIG. 24) of the combined syntax applied to the non-minimum CU size described in the modification of [2-1] is changed to the syntax definition table 112B13 shown in FIG. Further, the definition table 112B4 (FIG. 25) of the combined syntax applied to the minimum CU size described in the modification of [2-1] is changed to the syntax definition table 112B14 shown in FIG.

  First, the definition table 112B13 of the combined syntax applied to the non-minimum CU size will be described with reference to FIG. FIG. 48 is a diagram illustrating a configuration example of the syntax definition table 112B13 related to cu_split_pred_part_mode defined when the CU size is 16 × 16 or more (in the case of a non-minimum CU).

  In the definition table 112B13, the value of cu_split_pred_part_mode takes a value of “0” to “6”. The value of “4” is “inter-CU rectangular PU group and PU partition type group that is symmetric partition”, and the value of “5” is “inter-CU rectangular PU group and PU partition type that is asymmetric partition” Corresponding to “Group of”. The definition of each value “0” to “3” is the same as the definition table 112B3 in FIG. The definition of “6” in the definition table 112B13 is the same as the definition of the value “5” in the definition table 112B3 in FIG.

  When cu_split_pred_part_mode is “4” or “5”, the combined syntax determination unit 111 instructs the combined syntax decoding unit 1011 to decode horz_part_flag, which is a syntax for specifying the direction of the long side of the rectangular PU. . When cu_split_pred_part_mode is “5”, it further instructs the combined syntax decoding unit 1011 to further decode “rem_part_mode” in order to specify the PU partition type. In this case, if the value of rem_part_mode is “0”, it indicates that the PU partition type is “PART_2NxnU” or “PART_nLx2N”, and if the value of rem_part_mode is 1, the PU partition type is “PART_2NxnD” or “PART_nLx2N”. Indicates that there is.

  Next, with reference to FIG. 49, the definition table 112B14 of the combined syntax applied to the minimum CU size will be described. FIG. 49 is a diagram illustrating a configuration example of the syntax definition table 112B14 related to cu_split_pred_part_mode defined when the CU size is 8 × 8 (in the case of the minimum CU).

  In the definition table 112B14, the value of cu_split_pred_part_mode takes a value from “0” to “4”. The values “0”, “1”, “2”, “3”, and “4” are the definitions “1”, “2”, “3”, “4”, “6” in the definition table 112B13 of FIG. This is the same as the definition of each value of and is omitted.

  When cu_split_pred_part_mode is “3”, the combined syntax determination unit 111 instructs the combined syntax decoding unit 1011 to decode horz_part_flag, which is a syntax for specifying the direction of the long side of the rectangular PU.

  When cu_split_pred_part_mode is “4”, the combined syntax determination unit 111 instructs the combined syntax decoding unit 1011 to decode intra_part_mode, which is a syntax for specifying the PU partition type in the intra CU.

(Action / Effect)
As described above, a code amount reduction effect can be obtained by grouping PU division types that generally include rectangular PUs. However, when all PU partition types including rectangular PUs are grouped, if the asymmetric partition is applicable only in the non-minimum CU, the PU partition belonging to the “rectangular PU group” depending on whether it is the minimum CU or non-minimum CU. There is a problem that the types of types are different, and as a result, the process for specifying the types of PU partition types belonging to the “rectangular PU group” differs depending on whether the target CU is a minimum CU or a non-minimum CU. For example, the difference is that decoding of rem_part_mode is necessary for non-minimum CUs, but decoding of rem_part_mode is not necessary for minimum CUs. In the configuration of the modified example [9], by dividing the rectangular PU group into a group composed of a symmetric partition and a group composed of an asymmetric partition, the PU partition type belonging to the “rectangular PU that is a symmetric partition” is selected. The specified process is common to the minimum CU and non-minimum CU.

As described above, the present embodiment and each modified example described above are summarized as follows, particularly when the variable table is used.
<About the applicable syntax of the rectangular PU group>
As described in Modification [2-1], Modification [2-2], Modification [2-2-1], Modification [8-1], and Modification [8-2], PU partition type The method of grouping the rectangular PUs is a combined syntax with other various syntaxes (for example, CU partitioning flag, skip_flag, merge_flag, etc.) even when the PU partitioning information is an independent syntax. It can also be applied to cases. Further, as shown in the modification [3], the present invention can also be applied to a case where a part of the PU partition information (for example, inter 2N × 2N partition flag) is separately decoded. In other words, a syntax in which a part of possible values is a value corresponding to information for specifying a PU partition type is set as a group of rectangular PUs.
<About the rectangular PU group>
As shown in the modification [2], an effect is obtained when all non-square rectangular PUs that can be selected are grouped. Furthermore, as shown in the present embodiment and the modification [1], an effect can be obtained by grouping a part of non-square rectangular PUs. That is, an effect can be obtained by grouping PU partition types that include two or more PU partition types that divide a CU into non-square rectangular PUs.
<Adaptation of variable table>
This embodiment, modification [2], modification [2-1], modification [2-2], modification [2-2-1], modification [3], modification [8-1], According to the description of the modified example [8-2], the variable table is set for the syntax in which at least one of the possible values is a value corresponding to a PU division type group including the rectangular PU. When the value corresponding to the rectangular PU group is decoded, the variable table is updated so that a smaller code number is assigned to the PU partition type, thereby obtaining the effect of reducing the code amount in the present invention.

  From the above, the moving picture decoding apparatus according to the present invention can also be expressed as follows.

The moving picture decoding apparatus according to the present invention is a moving picture decoding apparatus that decodes a syntax in which a part of possible values is a value corresponding to information for specifying a PU partition type, and specifies the PU partition type. At least one of the values corresponding to the information to be performed is a value associated with a PU partition type group including two or more PU partition types that divide a CU into non-square rectangular PUs, and is included in the PU partition type group When the PU partition type to be decoded is decoded, a variable table update process corresponding to the syntax is executed so that a smaller code number is assigned to the PU partition type group.
[Moving picture encoding device]
Hereinafter, the moving picture coding apparatus 2 according to the present embodiment will be described with reference to FIG.

(Outline of video encoding device)
Generally speaking, the moving image encoding device 2 is a device that generates and outputs encoded data # 1 by encoding the input image # 10.

(Configuration of video encoding device)
First, a configuration example of the video encoding device 2 will be described with reference to FIG. FIG. 34 is a functional block diagram illustrating the configuration of the moving image encoding device 2. As shown in FIG. 34, the moving image encoding apparatus 2 includes an encoding setting unit 21, an inverse quantization / inverse conversion unit 22, a predicted image generation unit 23, an adder 24, a frame memory 25, a subtractor 26, a conversion / A quantization unit 27 and an encoded data generation unit (adaptive processing means) 29 are provided.

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

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

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

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

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

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

  The inverse quantization / inverse transform unit 22 performs inverse quantization and inverse orthogonal transform on the quantized prediction residual for each block supplied from the transform / quantization unit 27, thereby predicting the prediction residual for each block. To restore. The inverse orthogonal transform is as already described for the inverse quantization / inverse transform unit 13 shown in FIG.

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

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

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

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

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

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

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

  The transform / quantization unit 27 generates a prediction residual in the frequency domain by orthogonally transforming the prediction residual for each block, and then quantizes the prediction residual in the frequency domain to Generate quantized prediction residuals.

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

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

(Correspondence relationship with video decoding device)
The video encoding device 2 includes a configuration corresponding to each configuration of the video decoding device 1. Here, “correspondence” means that the same processing or the reverse processing is performed.

  For example, as described above, the prediction image generation process of the prediction image generation unit 14 included in the video decoding device 1 and the prediction image generation process of the prediction image generation unit 23 included in the video encoding device 2 are the same. .

  For example, the process of decoding a syntax value from a bit string in the video decoding device 1 corresponds to a process opposite to the process of encoding a bit string from a syntax value in the video encoding device 2. Yes.

  In the following, it will be described how each configuration in the video encoding device 2 corresponds to the CU information decoding unit 11, the PU information decoding unit 12, and the TU information decoding unit 13 of the video decoding device 1. . Thereby, the operation and function of each component in the moving image encoding device 2 will be clarified in more detail.

  The encoded data generation unit 29 corresponds to the decoding module 10. More specifically, the decoding module 10 derives a syntax value based on the encoded data and the syntax type, whereas the encoded data generation unit 29 encodes the code based on the syntax value and the syntax type. Generate data.

  Referring to FIG. 5 again, the case where the encoded data generation unit 29 performs encoding by the CAVLC encoding method will be schematically described as follows.

  The encoded data generation unit 29 refers to the variable table in which the syntax value and the code number are associated with each other, and derives the code number corresponding to the input syntax value.

  Furthermore, the encoded data generation unit 29 adaptively updates the variable table according to the generation of the syntax value.

  Note that the conversion between the code number and the syntax value by the variable table corresponds one-to-one between the moving picture decoding apparatus 1 and the moving picture encoding apparatus 2. For this reason, the processing relating to the variable table corresponds to that of the decoding module 10, and therefore detailed description thereof is omitted.

  Furthermore, the encoded data generation unit 29 encodes the bit string of the encoded data from the code number using the VLC method corresponding to the syntax and context. Since the VLC method also corresponds to that of the decoding module 10, detailed description thereof is omitted.

  In this way, the encoding process in the encoded data generation unit 29 is completed.

  The encoded data generation unit 29 has the same configuration as the combined syntax decoding unit 1011, variable table storage unit 1012, VLC method selection unit 1013, variable table selection unit 1014, and variable table adaptation unit 1015 provided in the decoding module 10. May be provided.

  The encoding setting unit 21 corresponds to the CU information decoding unit 11 of the video decoding device 1 described above. A comparison between the encoding setting unit 21 and the CU information decoding unit 11 described above is as follows.

  The CU information decoding unit 11 described above supplies the encoded data and the syntax type related to the combined syntax to the decoding module 10 and determines the PU partition type and the like based on the combined syntax decoded by the decoding module 10. .

  On the other hand, the encoding setting unit 21 determines a PU partition type and the like, generates a combined syntax, and supplies a syntax value and syntax type related to the combined syntax to the encoded data generation unit 29. .

  The encoding setting unit 21 may have the same configuration as the combined syntax determining unit 111 and the combined syntax (cu_split_pred_part_mode) definition table 112 included in the CU information decoding unit 11.

  The predicted image generation unit 23 corresponds to the PU information decoding unit 12 and the predicted image generation unit 14 of the video decoding device 1 described above. These are compared as follows.

  As described above, the PU information decoding unit 12 supplies the encoded data related to the motion information and the syntax type to the decoding module 10 and derives a motion compensation parameter based on the motion information decoded by the decoding module 10. Further, the predicted image generation unit 14 generates a predicted image based on the derived motion compensation parameter.

  On the other hand, the predicted image generation unit 23 determines the motion compensation parameter in the predicted image generation process, and supplies the syntax value and syntax type related to the motion compensation parameter to the encoded data generation unit 29.

  The transform / quantization unit 27 corresponds to the TU information decoding unit 13 and the inverse quantization / inverse transform unit 15 of the video decoding device 1 described above. These are compared as follows.

  The TU division setting unit 131 included in the TU information decoding unit 13 described above supplies encoded data and syntax type related to information indicating whether or not to perform node division to the decoding module 10 and is decoded by the decoding module 10. TU partitioning is performed based on information indicating whether or not to perform node partitioning.

  Further, the transform coefficient restoration unit 132 included in the TU information decoding unit 13 described above supplies the determination information, the encoded data related to the transform coefficient, and the syntax type to the decoding module 10, and the determination information decoded by the decoding module 10 and A conversion coefficient is derived based on the conversion coefficient.

  On the other hand, the transform / quantization unit 27 determines the division method of the TU division, and sends the syntax value and the syntax type related to the information indicating whether or not to perform node division to the encoded data generation unit 29. Supply.

  Also, the transform / quantization unit 27 supplies the encoded data generation unit 29 with the syntax value and syntax type related to the quantized transform coefficient obtained by transforming and quantizing the prediction residual.

(Correspondence with modification)
[1] Example of not using joint syntax (joint code) The encoded data generation unit 29 includes a CU partition flag (split_coding_unit_flag), a skip flag (skip_flag), a merge flag (merge_flag), CU prediction method information (PredMode), Also, split_pred_part_mode, which is a syntax that combines information of PU partition type information (PartMode), may be used, or a configuration that does not use such a syntax is also possible. Further, a configuration using the pred_part mode can be adopted.

  The specific configuration is the same as, for example, that described in the modification [1] of the video decoding device 1, and thus the description thereof is omitted here. However, “joining syntax determining unit 111”, “joining syntax decoding unit 1011”, “definition table 112A”, and “decoding (performing)” in the description of the modified example [1] are respectively referred to as “encoding setting unit”. 21 ”,“ encoded data generation unit 29 ”,“ configuration corresponding to the definition table 112A ”, and“ encoding (perform) ”.

[2] 'Example in which vertical and horizontal are not distinguished The encoded data generation unit 29 may distinguish a horizontally-long rectangular PU group from a vertically-long rectangular PU group, or a group of non-square PU partition types without distinguishing both. May be handled as

[2-1] Using 'horz_part_flag horz_part_flag that specifies whether a PU partition type belongs to a horizontally long rectangular PU group or a vertically long rectangular PU group can be used.

  The specific configuration is the same as that described in the modified example [2-1] of the video decoding device 1, for example, and thus the description thereof is omitted here. However, the “join syntax determining unit 111”, “syntax definition table 112B1”, “syntax definition table 112B2”, and “decoding (performing)” in the description of the modified example [2-1] “Configuration setting unit 21”, “configuration corresponding to syntax definition table 112B1”, “configuration corresponding to syntax definition table 112B2”, and “encoding (perform)”.

[2-2] ′ Further, in the case of using a combination syntax (joint code) The encoding setting unit 21 and the encoded data generation unit 29 change cu_split_pred_part_mode instead of pred_part_mode used in the modified example [2-1] ′. The structure to be used may be used.

  For example, the specific configuration is the same as that described in the modification [2-2] of the video decoding device 1, and thus the description thereof is omitted here. However, “joined syntax determining unit 111”, “joined syntax decoding unit 1011”, “definition table 112B3”, “definition table 112B4”, and “decoding (performing)” in the description of the modified example [2-2] are used. , “Encoding setting unit 21”, “encoded data generation unit 29”, “configuration corresponding to definition table 112B3”, “configuration corresponding to definition table 112B4”, and “encoding (perform)”, respectively. Shall.

[2-2-1] Further, when a common syntax definition table is used The encoding setting unit 21 and the encoded data generation unit 29 further define a combined syntax definition table in a configuration that does not distinguish between vertical and horizontal. A common configuration may be used.

  The specific configuration is the same as that described in, for example, the modified example [2-2-1] of the video decoding device 1, and thus the description thereof is omitted here. However, the “join syntax determining unit 111”, “definition table 112B6”, “table for variable table initialization” and “decoding (performing)” in the description of the modified example [2-2-1] are “ It shall be read as “encoding setting unit 21”, “configuration corresponding to definition table 112B6”, “configuration corresponding to variable table initialization table” and “encoding (perform)”.

[2-3] ′ Further, in the case where AMP is prohibited The encoding setting unit 21 and the encoded data generation unit 29 may be configured so as not to distinguish between vertical and horizontal directions and further not to use AMP. The specific configuration is the same as that described in, for example, the modification [2-3] of the video decoding device 1, and thus the description thereof is omitted here. However, the “joined syntax determining unit 111”, “joined syntax decoding unit 1011”, “definition table 112B5”, and “decoding (performing)” in the description of the modified example [2-3] are “encoding”. It should be read as “setting unit 21”, “encoded data generating unit 29”, “configuration corresponding to definition table 112B5”, and “encoding (perform)”.

[2-4] ′ Further, in the case of using CABAC The encoding setting unit 21 and the encoded data generation unit 29 may be configured to further use CABAC in a configuration that does not distinguish between vertical and horizontal. The specific configuration is the same as that described in, for example, the modification [2-4] of the video decoding device 1, and thus the description thereof is omitted here. However, “joined syntax decoding unit 1011” and “(arithmetic) decoding (performing)” in the description of the modified example [2-4] are respectively referred to as “encoded data generation unit 29” and “(arithmetic)”. It shall be read as “encoding”. The binarization in the description of the modification [2-4] is performed by the “encoded data generation unit 29”.

[3] ′ Use of Inter 2N × 2N Flag The encoding setting unit 21 and the encoded data generation unit 29 may be configured to express the PU partition type by combining pred_part_mode and the inter 2N × 2N flag.

  The specific configuration is the same as that described in the modification [3] of the video decoding device 1, for example, and thus the description thereof is omitted here. However, the “joined syntax determining unit 111”, “joined syntax decoding unit 1011”, “syntax definition table 112C”, and “decoding (performing)” in the description of the modified example [3] are “encoding”. It should be read as “setting unit 21”, “encoded data generation unit 29”, “configuration corresponding to syntax definition table 112C”, and “encoding (perform)”.

[4] 'Variation of Variable Table Adaptation Processing The encoding setting unit 21 and the encoded data generation unit 29 may be configured to perform variable table adaptation processing by assigning independent syntax values to each PU partition type. .

  The specific configuration is the same as that described in the modification [4] of the video decoding device 1, for example, and thus the description thereof is omitted here. However, “variable table adaptation unit 1015”, “variable table 1012E”, and “decoding (perform)” in the description of modification [4] correspond to “encoded data generation unit 29” and “variable table 1012E”, respectively. It shall be read as “configuration to do” and “encoding (to do)”. Further, it is assumed that the variable table adaptation process is performed according to the number of occurrences of the syntax value.

[5] Application of 'CABAC The encoded data generation unit 29 may perform arithmetic encoding by CABAC in a configuration in which vertical and horizontal are distinguished.

  The specific configuration is the same as that described in the modification [5] of the video decoding device 1, for example, and thus the description thereof is omitted here. However, “joined syntax decoding unit 1011”, “table TBL21”, and “(arithmetic) decoding (perform)” in the description of the modified example [5] are respectively referred to as “encoded data generation unit 29” and “table TBL21”. To “configuration corresponding to” and “(arithmetic) encoding (to)”.

[6] ′ Variable table adaptation using a counter The encoded data generation unit 29 may perform variable table adaptation using a counter. The specific configuration is the same as that described in the modification [6] of the video decoding device 1, for example, and thus the description thereof is omitted here. However, the “joined syntax decoding unit 1011”, “variable table 1012F”, “variable table 1012G”, and “decoding” (decoding) in the description of the modified example [6] are respectively “encoded data generation unit 29”. , “Configuration corresponding to the variable table 1012F”, “configuration corresponding to the variable table 1012G”, and “encoding (perform)”. Further, it is assumed that the variable table adaptation process is performed according to the number of occurrences of the syntax value.

[7] ′ Example of grouping PU partition types having the same number of partitions The encoded data generation unit 29 may be configured to group PU partition types having the same number of partitions. The specific configuration is the same as that described in the modification [7] of the video decoding device 1, for example, and the description thereof is omitted here. However, the “joined syntax decoding unit 1011”, “syntax definition table 112B7”, “syntax definition table 112B8”, and “decoding (performing)” in the description of the modified example [7] are “encoded data”, respectively. The “generation unit 29”, “configuration corresponding to the syntax definition table 112B7”, “configuration corresponding to the syntax definition table 112B8”, and “encoding (perform)” shall be read.

[8] 'Example of different syntax The encoding setting unit 21 and the encoded data generation unit 29 use a combination of a CU partition flag, a skip flag, a merge flag, CU prediction method information, and PU partition type information as a combined syntax. A configuration using a combination other than the above may also be used.

[8-1] 'When the combined syntax does not include information related to the merge flag The encoding setting unit 21 and the encoded data generation unit 29 are configured so that the value of the combined syntax does not include information related to the merge flag. Also good. The specific configuration is the same as that described in the modification [8-1] of the video decoding device 1, and thus the description thereof is omitted here. However, in the description of the modified example [8-1], “joined syntax determination unit 111”, “joint syntax decoding unit 1011”, “syntax definition table 112B9”, “syntax definition table 112B10”, and “decoding ( "Encoding setting unit 21", "encoded data generation unit 29", "configuration corresponding to syntax definition table 112B9", "configuration corresponding to syntax definition table 112B10", and " It shall be read as “encoding”.

[8-2] 'When the combined syntax does not include information on the CU partitioning flag The encoding setting unit 21 and the encoded data generation unit 29 have a configuration in which the value of the combined syntax does not include information on the CU partitioning flag. May be. The specific configuration is the same as that described in the modification [8-2] of the video decoding device 1, and thus the description thereof is omitted here. However, in the description of the modified example [8-2], “joined syntax determination unit 111”, “joint syntax decoding unit 1011”, “syntax definition table 112B11”, “syntax definition table 112B12”, and “decoding ( "Encoding setting unit 21", "encoded data generation unit 29", "configuration corresponding to syntax definition table 112B11", "configuration corresponding to syntax definition table 112B12", and " It shall be read as “encoding”.

[9] 'When asymmetric partitions are grouped The encoded data generation unit 29 may be configured to group asymmetric partitions. The specific configuration is the same as that described in the modification [9] of the video decoding device 1, and thus the description thereof is omitted here. However, the “joined syntax decoding unit 1011”, “syntax definition table 112B13”, “syntax definition table 112B14”, and “decoding (performing)” in the description of the modified example [9] are referred to as “encoded data”. It shall be read as “generation unit 29”, “configuration corresponding to syntax definition table 112B13”, “configuration corresponding to syntax definition table 112B14”, and “encoding (to)”.
[Appendix 1]
In the description of the video decoding device and the video encoding device in the above embodiment, an example in which a PU partition type belonging to a rectangular PU group is included in a part of the PU partition type of the inter CU has been described. I can't. For example, when a PU partition type belonging to a non-square rectangular PU group is included as part of the intra-PU PU partition type, a value corresponding to the non-square rectangular PU group in the intra CU is set as the value of the combined syntax cu_split_pred_part_mode May be. Even in an intra CU, PU partition types belonging to a rectangular PU group tend to be selected in a region having a similar region complexity, so that the code amount can be reduced by adaptive processing. In addition, when the PU division including the rectangular PU can be selected for both the intra CU and the inter CU, it is preferable to separately set the rectangular PU group in the intra CU and the rectangular PU group in the inter CU. In other words, it is preferable to associate a certain value of the combined syntax with the rectangular PU group of the intra CU and associate another value of the combined syntax with the rectangular PU group of the inter CU. In general, intra CUs tend to be selected in more complex areas than inter CUs. For this reason, even in the same rectangular PU group, there is a tendency to be selected in regions of different complexity depending on whether it is an intra CU or an inter CU. Therefore, by setting different values for the rectangular PU group of the intra CU and the rectangular PU group of the inter CU, it is possible to assign a shorter code to an appropriate group according to the complexity of the region, thereby improving coding efficiency. To do.

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

  First, it will be described with reference to FIG. 27 that the above-described moving image encoding device 2 and moving image decoding device 1 can be used for transmission and reception of moving images.

  FIG. 35A is a block diagram illustrating a configuration of a transmission apparatus PROD_A in which the moving image encoding apparatus 2 is mounted. As illustrated in (a) of FIG. 35, the transmission device PROD_A modulates a carrier wave with an encoding unit PROD_A1 that obtains encoded data by encoding a moving image, and the encoded data obtained by the encoding unit PROD_A1. Thus, a modulation unit PROD_A2 that obtains a modulation signal and a transmission unit PROD_A3 that transmits the modulation signal obtained by the modulation unit PROD_A2 are provided. The moving image encoding apparatus 2 described above is used as the encoding unit PROD_A1.

  The transmission device PROD_A is a camera PROD_A4 that captures moving images, a recording medium PROD_A5 that records moving images, an input terminal PROD_A6 that inputs moving images from the outside, as a supply source of moving images that are input to the encoding unit PROD_A1 An image processing unit A7 that generates or processes an image may be further provided. FIG. 35A illustrates a configuration in which the transmission apparatus PROD_A includes all of these, but some of them 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. 35B is a block diagram illustrating a configuration of the receiving device PROD_B in which the video decoding device 1 is mounted. As illustrated in (b) of FIG. 35, the reception device PROD_B includes a reception unit PROD_B1 that receives a modulation signal, a demodulation unit PROD_B2 that obtains encoded data by demodulating the modulation signal received by the reception unit PROD_B1, and a demodulation A decoding unit PROD_B3 that obtains a moving image by decoding the encoded data obtained by the unit PROD_B2. The moving picture decoding apparatus 1 described above is used as the decoding unit PROD_B3.

  The receiving device PROD_B has a display PROD_B4 for displaying a moving image, a recording medium PROD_B5 for recording the moving image, and an output terminal for outputting the moving image to the outside as a supply destination of the moving image output by the decoding unit PROD_B3. PROD_B6 may be further provided. FIG. 35B 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.

  Next, it will be described with reference to FIG. 36 that the above-described moving image encoding device 2 and moving image decoding device 1 can be used for recording and reproduction of moving images.

  FIG. 36A is a block diagram showing a configuration of a recording apparatus PROD_C in which the above-described moving picture encoding apparatus 2 is mounted. As shown in (a) of FIG. 36, the recording apparatus PROD_C has an encoding unit PROD_C1 that obtains encoded data by encoding a moving image, and the encoded data obtained by the encoding unit PROD_C1 on the recording medium PROD_M. A writing unit PROD_C2 for writing. The moving image encoding apparatus 2 described above is used as the encoding unit PROD_C1.

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

  The recording device PROD_C is a camera PROD_C3 that captures moving images as a supply source of moving images to be input to the encoding unit PROD_C1, an input terminal PROD_C4 for inputting moving images from the outside, and reception for receiving moving images. The unit PROD_C5 and an image processing unit C6 that generates or processes an image may be further provided. In FIG. 36A, a configuration in which the recording apparatus PROD_C includes all of these is illustrated, but a part of the configuration may be omitted.

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

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

  FIG. 36 (b) is a block diagram illustrating a configuration of a playback device PROD_D in which the above-described video decoding device 1 is mounted. As shown in (b) of FIG. 36, the playback device PROD_D reads the moving image by decoding the reading unit PROD_D1 that reads the encoded data written on the recording medium PROD_M and the encoded data read by the reading unit PROD_D1. And a decoding unit PROD_D2 to be obtained. The moving picture decoding apparatus 1 described above is used as the decoding unit PROD_D2.

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

  In addition, the playback device PROD_D has a display PROD_D3 that displays a moving image, an output terminal PROD_D4 that outputs the moving image to the outside, and a transmission unit that transmits the moving image as a supply destination of the moving image output by the decoding unit PROD_D2. PROD_D5 may be further provided. FIG. 36B 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.

(Hardware implementation and software implementation)
Each block of the moving picture decoding apparatus 1 and the moving picture encoding apparatus 2 described above may be realized in hardware by a logic circuit formed on an integrated circuit (IC chip), or may be a CPU (Central Processing). Unit) may be implemented in software.

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

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

  Further, each of the above devices may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited as long as it can transmit the program code. For example, Internet, Intranet, Extranet, LAN (Local Area Network), ISDN (Integrated Services Digital Network), VAN (Value-Added Network), CATV (Community Antenna television / Cable Television) communication network, Virtual Private Network (Virtual Private Network) Network), telephone line network, mobile communication network, satellite communication network, and the like. The transmission medium constituting the communication network may be any medium that can transmit the program code, and is not limited to a specific configuration or type. For example, infra-red such as IrDA (Infrared Data Association) or remote control, 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 can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  The present invention can be suitably applied to an image decoding apparatus that decodes encoded data obtained by encoding image data and an image encoding apparatus that generates encoded data obtained by encoding image data. Further, the present invention can be suitably applied to the data structure of encoded data generated by an image encoding device and referenced by the image decoding device.

1 video decoding device (image decoding device)
DESCRIPTION OF SYMBOLS 10 Decoding module 11 CU information decoding part 16 Frame memory 111 Connection syntax determination part (additional information decompression | restoration means)
112 Definition Table 113 PU Partition Type Definition Table 114 PU Partition Type Residual Information Definition Table 1011 Combined Syntax Decoding Unit (Decoding Unit, Prediction Unit Division Type Group Acquisition Unit, Additional Information Restoration Unit, Arithmetic Decoding Unit)
1012 Variable table storage unit 1013 VLC method selection unit 1014 Variable table selection unit 1015 Variable table adaptation unit (adaptive processing means)
2 Video encoding device (image encoding device)
21 Encoding setting unit 25 Frame memory 29 Encoded data generation unit (adaptive processing means)

Claims (17)

In an image decoding apparatus that generates a prediction image and restores an image for each prediction unit obtained by dividing a coding unit into a number of one or more according to a predetermined prediction unit division type,
As the predetermined prediction unit division type, there are a plurality of rectangular prediction unit division types that are prediction unit division types into rectangular prediction units,
At least a part of the possible values is a syntax that is a value used for specifying a prediction unit division type, and at least one of the values used for specifying the prediction unit division type is a rectangular prediction unit division type. Syntax decoding means for decoding syntax that is a value associated with the prediction unit division type group including the above,
When a prediction unit partition type included in the prediction unit partition type group is decoded, a variable table used for decoding the syntax is updated so that a smaller code number is assigned to the prediction unit partition type group. An image decoding apparatus comprising an adaptive processing means.   2. The syntax according to claim 1, wherein the syntax is a combined syntax of at least one of coding unit partition information, skip flag, merge flag, and CU prediction scheme information, and prediction unit partition type information. Image decoding apparatus.   The image decoding apparatus according to claim 2, wherein the syntax is a combined syntax of coding unit division information, skip flag, CU prediction scheme information, and prediction unit division type.   The image decoding apparatus according to claim 2, wherein the syntax is a combined syntax of a skip flag, a merge flag, CU prediction method information, and a prediction unit division type. As the prediction unit division type group, a set of a symmetric rectangular prediction unit division type group that is a set of symmetric partition prediction unit division types including a rectangular prediction unit and a set of prediction unit division types of an asymmetric partition that includes a rectangular prediction unit. Is defined as at least an asymmetric rectangular prediction unit partition type group,
The first value that the syntax can take is a value associated with the symmetric rectangular prediction unit partition type group,
5. The image decoding apparatus according to claim 1, wherein the second value that the syntax can take is a value associated with the asymmetric rectangular prediction unit division type group. 6. As the prediction unit division type group, there are an intra rectangular prediction unit division type group including a rectangular prediction unit in an intra coding unit and an inter rectangular prediction unit division type group including a rectangular prediction unit in an inter coding unit. At least prescribed,
The first value that the syntax can take is a value associated with the intra rectangular prediction unit division type group,
6. The image decoding apparatus according to claim 1, wherein the second value that the syntax can take is a value associated with the inter-rectangular prediction unit division type group. In an image encoding device that generates a prediction image for each prediction unit obtained by dividing a coding unit into a number of one or more according to a predetermined prediction unit division type,
As the predetermined prediction unit division type, there are a plurality of rectangular prediction unit division types that are prediction unit division types into rectangular prediction units,
At least a part of the possible values is a syntax that is a value used for specifying a prediction unit division type, and at least one of the values used for specifying the prediction unit division type is a rectangular prediction unit division type. Syntax encoding means for encoding syntax that is a value associated with the prediction unit partition type group including the above,
Adapting to update a variable table used for decoding the syntax so that a smaller code number is assigned to the prediction unit division type group when a prediction unit division type included in the prediction unit division type group occurs An image coding apparatus comprising processing means. In an image decoding apparatus that generates a prediction image and restores an image for each prediction unit obtained by dividing a coding unit into a number of one or more according to a predetermined prediction unit division type,
As the predetermined prediction unit division type, there are a plurality of rectangular prediction unit division types that are prediction unit division types into rectangular prediction units,
A prediction unit division type group to which two or more rectangular prediction unit division types belong is defined,
When the rectangular prediction unit partition type belonging to the prediction unit partition type group is restored for the coding unit to be processed, each rectangular prediction unit partition type belonging to the prediction unit partition type group is shorter than before decoding. An image decoding apparatus comprising: adaptive processing means for performing adaptive processing so that a code is decoded.   The prediction unit division type group is defined as a union of a set of prediction unit division types into horizontally long rectangular prediction units and a set of prediction unit division types into vertically long rectangular prediction units. 8. The image decoding device according to 8.   9. The prediction unit division type group is defined as a set of prediction unit division types into horizontally long rectangular prediction units or a set of prediction unit division types into vertically long rectangular prediction units. Image decoding apparatus. The decoding means for decoding the code number from each code included in the encoded data, the prediction unit division type group, and a variable table including a correspondence between the code number corresponding to the prediction unit division type group, A prediction unit division type group obtaining unit for obtaining a prediction unit division type group corresponding to the code number decoded from the coded data,
The adaptive process by the adaptive processing means is a variable table adaptive process in which the variable table is updated so that a smaller code number is associated with the obtained prediction unit division type group. The image decoding device according to any one of 8 to 10.   An additional information restoring unit that restores additional information for specifying which prediction unit division type is the rectangular prediction unit division type belonging to the prediction unit division type group acquired by the prediction unit division type group acquisition unit; The image decoding apparatus according to claim 11, further comprising: The prediction unit partition type group includes a prediction unit partition type of a symmetric partition and a prediction unit partition type of an asymmetric partition,
The image decoding apparatus according to claim 12, wherein in the additional information, a shorter code is assigned to a prediction unit division type of a symmetric partition than a prediction unit division type of an asymmetric partition. An arithmetic decoding unit that arithmetically decodes a binary value indicating whether a prediction unit division type in a coding unit to be processed is included in the prediction unit division type group;
9. The image decoding apparatus according to claim 8, wherein the adaptive processing by the adaptive processing means is processing for updating a probability table used in arithmetic decoding of the binary value. The above prediction unit partition type group in which the prediction unit partition type in the coding unit to be processed is defined as a set of prediction unit partition types into horizontally long rectangular prediction units, and the prediction unit partition type into vertically long rectangular prediction units Arithmetic decoding means for arithmetically decoding binary values indicating which of the prediction unit division type groups defined as a set of
15. The image decoding apparatus according to claim 14, wherein the adaptive processing by the adaptive processing means is processing for updating a probability table used in arithmetic decoding of the binary value. In an image encoding device that generates a prediction image for each prediction unit obtained by dividing a coding unit into a number of one or more according to a predetermined prediction unit division type,
As the predetermined prediction unit division type, there are a plurality of rectangular prediction unit division types that are prediction unit division types into rectangular prediction units,
A prediction unit division type group to which two or more rectangular prediction unit division types belong is defined,
When a rectangular prediction unit division type belonging to the prediction unit division type group occurs for the coding unit to be processed, each rectangular prediction unit division type belonging to the prediction unit division type group is shorter than before generation. An image encoding apparatus comprising: adaptive processing means for adaptively processing so that a code is assigned. In order to obtain a prediction unit for generating a prediction image, encoded data including prediction unit division information for specifying a predetermined prediction unit division type, which is a division method for dividing an encoding unit into one or more numbers. In the data structure:
In the image decoding apparatus for decoding the encoded data, there are a plurality of rectangular prediction unit division types that are prediction unit division types into rectangular prediction units as the predetermined prediction unit division type, and the rectangular prediction unit division type Predictive unit split type group to which two or more belong is defined,
The encoded data specifies which rectangular prediction unit division type that belongs to the prediction unit division type group that is encoded when the prediction unit division type group is designated. A data structure of encoded data, characterized by including additional information for:

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