Patent Publication Number: US-2023133884-A1

Title: Moving picture coding method, moving picture coding apparatus, moving picture decoding method, and moving picture decoding apparatus

Description:
FIELD 
     The present disclosure relates to a moving picture coding method, a moving picture coding apparatus, a moving picture decoding method, and a moving picture decoding apparatus. 
     BACKGROUND 
     In moving picture coding processing, in general, the amount of information is reduced by utilizing redundancy in the spatial direction and the temporal direction which moving pictures have. Here, in general, transform to a frequency domain is used as a method utilizing redundancy in the spatial direction. Further, inter-picture prediction (hereinafter, referred to as “inter prediction”) coding processing is used as a method utilizing redundancy in the temporal direction. In inter prediction coding processing, when a picture is coded, a coded picture that appears before or after a current picture to be coded in the display time order is used as a reference picture. A motion vector is derived by performing motion detection on the current picture relative to the reference picture. Then, redundancy in the temporal direction is eliminated by calculating a difference between image data of the current picture and predicted image data obtained by motion compensation based on the derived motion vector. 
     CITATION LIST 
     Non Patent Literature 
     
         
         [NPL 1] ITU-T H.264 “8.4.1 Derivation process for motion vector components and reference indices” March, 2010, Expressions (8-174) and (8-175) 
         [NPL 2] JCTVC-F803_d2 “WD4: Working Draft 4 of High-Efficiency Video Coding”, Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11 6th Meeting, Torino, IT, 14 to 22 Jul. 2011 
       
    
     SUMMARY 
     Technical Problem 
     There is a demand, however, for the above conventional technique to achieve an increase in processing speed in coding and decoding a moving picture using inter prediction. 
     In view of this, an object of the present disclosure is to provide a moving picture coding method and a moving picture decoding method for allowing an increase in the processing speed of coding and decoding a moving picture using inter prediction. 
     Solution to Problem 
     A moving picture coding method according to an aspect of the present disclosure is a moving picture decoding method for decoding a current block included in a bitstream, using a motion vector predictor used when decoding a motion vector of the current block, the method including: (a) obtaining one or more motion vector predictor candidates which are candidates for the motion vector predictor; (b) decoding a coded index for identifying one of the one or more motion vector predictor candidates, the coded index being added to the bitstream; and (c) selecting, based on the decoded index, the motion vector predictor to be used for decoding the current block from among the one or more motion vector predictor candidates, wherein step (a) includes: (a1) generating a motion vector predictor candidate, based on plural motion vectors of plural first adjacent blocks adjacent to the current block in a first direction; and (a2) generating a motion vector predictor candidate, based on plural motion vectors of plural second adjacent blocks adjacent to the current block in a second direction, and step (a2) includes: (i) determining whether the plural first adjacent blocks include one or more inter-predicted blocks; and (ii) searching for a motion vector to be made available by scaling processing from among the plural motion vectors of the plural second adjacent blocks when it is determined in step (i) that the plural first adjacent blocks do not include an inter-predicted block, and generating, when the motion vector is obtained in the search, one of the one or more motion vector predictor candidates by executing scaling processing on the motion vector obtained in the search. 
     It should be noted that these general and specific aspects may be implemented using a system, a method, an integrated circuit, a computer program, a computer-readable recording medium such as a CD-ROM, or any combination of systems, methods, integrated circuits, computer programs or recording media. 
     Further benefits and advantages provided by the disclosed embodiments become clear from the specification and the drawings. Those benefits and advantages may be individually achieved by the features of various embodiments, the specification, and the drawings, and all the features do not necessarily need to be provided to obtain at least one benefit or advantage. 
     Advantageous Effects 
     Provided is a moving picture coding method and a moving picture decoding method for allowing an increase in the processing speed of coding and decoding a moving picture using inter prediction. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       These and other objects, advantages and features of the disclosure will become apparent from the following description thereof taken in conjunction with the accompanying drawings that illustrate a specific embodiment of the present disclosure. 
         FIG.  1    is a conceptual diagram illustrating a relationship among a motion vector, a motion vector predictor, and a motion vector difference which are used to generate a predicted image. 
         FIG.  2    is a block diagram illustrating an example of a configuration of a moving picture coding apparatus. 
         FIG.  3    is a flowchart illustrating an example of a moving picture coding method. 
         FIG.  4 A  illustrates a relationship between coding block units CU (coding unit) and prediction block units PU (prediction unit). 
         FIG.  4 B  illustrates a relationship between a coding unit tree and pred_type. 
         FIG.  4 C  illustrates an interpretation table for values of pred_type. 
         FIG.  5    illustrates a positional relationship between a current block to be predicted and adjacent blocks adjacent to the current block. 
         FIG.  6 A  illustrates a candidate list mvpListL 0  of motion vector predictors. 
         FIG.  6 B  illustrates a candidate list mvpListL 1  of motion vector predictors. 
         FIG.  7    is a conceptual diagram illustrating a relationship between motion vector predictor candidates included in a candidate list mvpListLX. 
         FIG.  8    is a flowchart illustrating a procedure of creating a candidate list mvpListLX according to Comparative Example. 
         FIG.  9 A  is a flowchart illustrating a detailed processing procedure of step S 410  in  FIG.  8   . 
         FIG.  9 B  is a flowchart illustrating a detailed processing procedure of step S 430  in  FIG.  8   . 
         FIG.  10 A  is a flowchart illustrating a detailed procedure of step S 510  in  FIG.  8   . 
         FIG.  10 B  is a flowchart illustrating a detailed procedure of step S 530  in  FIG.  8   . 
         FIG.  11    is a flowchart illustrating a detailed procedure of step S 240  in  FIG.  3   . 
         FIG.  12    is a flowchart illustrating a detailed procedure of step S 250  in  FIG.  3   . 
         FIG.  13    illustrates a problem of mvpListLX generation processing. 
         FIG.  14    illustrates a method for generating mvpListLX used by a moving picture coding apparatus according to Embodiment 1. 
         FIG.  15    is a block diagram illustrating a configuration of a moving picture decoding apparatus according to Embodiment 2. 
         FIG.  16    is a flowchart illustrating a moving picture decoding method according to Embodiment 2. 
         FIG.  17    is a flowchart illustrating a procedure of creating a candidate list mvpListLX in Embodiment 2. 
         FIG.  18    sequentially illustrates a procedure of creating the candidate list mvpListLX in Embodiment 2. 
         FIG.  19    illustrates a determination result obtained in steps S 620  and S 820  when a current block to be predicted is PU 0 . 
         FIG.  20    illustrates a determination result obtained in steps S 620  and S 820  when a current block to be predicted is PU 1 . 
         FIG.  21    is a partial flowchart illustrating a procedure of creating the candidate list mvpListLX in Variation 1. 
         FIG.  22    is a flowchart illustrating a procedure of creating the candidate list mvpListLX in Variation 2. 
         FIG.  23    sequentially illustrates a procedure of creating the candidate list mvpListLX in Variation 2. 
         FIG.  24    shows an overall configuration of a content providing system for implementing content distribution services. 
         FIG.  25    shows an overall configuration of a digital broadcasting system. 
         FIG.  26    shows a block diagram illustrating an example of a configuration of a television. 
         FIG.  27    shows a block diagram illustrating an example of a configuration of an information reproducing/recording unit that reads and writes information from and on a recording medium that is an optical disk. 
         FIG.  28    shows an example of a configuration of a recording medium that is an optical disk. 
         FIG.  29 A  shows an example of a cellular phone. 
         FIG.  29 B  is a block diagram showing an example of a configuration of a cellular phone. 
         FIG.  30    illustrates a structure of multiplexed data. 
         FIG.  31    schematically shows how each stream is multiplexed in multiplexed data. 
         FIG.  32    shows how a video stream is stored in a stream of PES packets in more detail. 
         FIG.  33    shows a structure of TS packets and source packets in the multiplexed data. 
         FIG.  34    shows a data structure of a PMT. 
         FIG.  35    shows an internal structure of multiplexed data information. 
         FIG.  36    shows an internal structure of stream attribute information. 
         FIG.  37    shows steps for identifying video data. 
         FIG.  38    shows an example of a configuration of an integrated circuit for implementing the moving picture coding method and the moving picture decoding method according to each of embodiments. 
         FIG.  39    shows a configuration for switching between driving frequencies. 
         FIG.  40    shows steps for identifying video data and switching between driving frequencies. 
         FIG.  41    shows an example of a look-up table in which video data standards are associated with driving frequencies. 
         FIG.  42 A  is a diagram showing an example of a configuration for sharing a module of a signal processing unit. 
         FIG.  42 B  is a diagram showing another example of a configuration for sharing a module of the signal processing unit. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Underlying Knowledge Forming Basis of the Present Disclosure 
     In H.264, three picture types, namely, I-picture, P-picture, and B-picture are used to compress the amount of information. 
     An I-picture is not coded by inter prediction coding processing. Specifically, an I-picture is coded by intra-picture prediction (hereinafter, referred to as intra prediction) coding processing. A 
     P-picture is coded by inter prediction coding by referring to one already coded picture that appears before or after a current picture to be coded in the display time order. A B-picture is coded by inter prediction coding by referring to two already coded pictures that appear before (e.g., in a prediction direction 0) or after (e.g., in a prediction direction 1) the current picture in the display time order. 
     Various considerations are being made regarding a motion vector deriving method used for inter prediction coding processing on a moving picture. Examples of the motion vector deriving method include the methods below. 
     The first motion vector deriving method is an H.264 direct mode for directly deriving a motion detection vector (motion vector) from coded (decoded) data, without obtaining information from a code string. 
     The second motion vector deriving method is a method for deriving a motion vector v (motion vector) to be used for inter prediction by adding a motion vector difference d obtained from a code string to a motion vector predictor p (see Expressions (8-174) and (8-175) in NPL 1, for instance). It should be noted that the motion vector difference d is a difference vector between the motion vector v and the motion vector predictor p. 
     Here,  FIG.  1    is a conceptual diagram illustrating a relationship among the motion vector v (mvLX), the motion vector predictor p (mvpLX), and the motion vector difference d (mvdLX) in the second H.264 motion vector deriving method. It should be noted that calculation is performed separately for first components (e.g., horizontal components) and second components (e.g., vertical components) in the example illustrated in  FIG.  1   . 
     At the time of decoding, the motion vector mvLX is reconstructed by executing the calculation of Expressions 1 and 2 below for respective components. 
       For a first component: mvLX[0]=mvpLX[0]+mvdLX[0]  (Expression 1)
 
       For a second component: mvLX[1]=mvpLX[1]+mvdLX[1]  (Expression 2)
 
     At the time of coding, first, a motion vector mvLX (mvLX [0], mvLX [1]) is determined through search in view of coding efficiency (and also refIdxLX for identifying a reference image). Furthermore, calculations represented by Expressions 3 and 4 below are performed in order to obtain a motion vector difference mvdLX which is information necessary for reconstructing the motion detection vector mvLX. 
       For a first component: mvdLX[0]=mvLX[0]−mvpLX[0]  (Expression 3)
 
       For a second component: mvdLX[1]=mvLX[1]− mvpLX  (Expression 4)
 
     At the time of coding, the two-dimensional motion vector difference mvdLX (mvdLX [0], mvdLX [1]) obtained by the above calculations is coded. 
     The following is a description of a moving picture coding method and a moving picture coding apparatus according to Comparative Example, based on  FIGS.  2  to  5   . 
     EX1: Configuration of Moving Picture Coding Apparatus According to Comparative Example 
       FIG.  2    is a block diagram illustrating an example of a configuration of the moving picture coding apparatus according to Comparative Example. 
     As illustrated in  FIG.  2   , a moving picture coding apparatus  100  includes a difference unit  101 , a transform unit  102 , a quantization unit  103 , an entropy coding unit  110 , an inverse quantization unit  104 , an inverse transform unit  105 , an addition unit  106 , a memory  109 , an intra/inter prediction unit  107 , and a coding control unit  108 . 
     The difference unit  101  generates a residual signal by subtracting a predicted image signal from an input image signal for each block. The difference unit  101  outputs the residual signal to the transform unit  102 . 
     The transform unit  102  transforms the residual signal from an image domain into a frequency domain. The quantization unit  103  performs quantization processing on the residual signal which has been transformed into the frequency domain. The quantization unit  103  outputs the quantized residual signal which is a residual signal on which quantization processing has been performed to the inverse quantization unit  104  and the entropy coding portion  110 . 
     The entropy coding unit  110  performs entropy coding processing on the quantized residual signal, a decoding control signal, and the like, to generate a coded bitstream. A decoding control signal includes a prediction direction flag, picture type information, a control parameter such as a motion vector difference d, for example. 
     The inverse quantization unit  104  performs inverse quantization processing on the quantized residual signal on which quantization processing has been performed by the quantization unit  103 . The inverse transform unit  105  transforms the quantized residual signal (residual signal) on which inverse quantization processing has been performed from the frequency domain into the image domain, and outputs a reconstructed residual signal. 
     The addition unit  106  adds a reconstructed residual signal and a predicted image signal for each block to be coded, thereby generating a reconstructed image signal. 
     A reconstructed image signal is stored on a frame-by-frame basis in the memory  109 . 
     The intra/inter prediction unit  107  stores a reconstructed image signal in a memory in predetermined units, such as frame units and block units. In addition, the intra/inter prediction unit  107  generates a predicted image signal (a pixel value derived based on a reconstructed image signal and a motion vector), based on an instruction from the coding control unit  108  described below. The intra/inter prediction unit  107  outputs the generated predicted image signal to the difference unit  101  and the addition unit  106 . 
     The coding control unit  108  determines which control parameter is to be used for coding a picture (input image signal), after making trials. The coding control unit  108  outputs, from among plural control parameters, a control parameter (coding control information) necessary for coding to the intra/inter prediction unit  107 . More specifically, for example, as shown by the dotted lines in  FIG.  1   , the coding control unit  108  obtains a coded bitstream, determines plural control parameters (e.g., for distinguishing between inter prediction and intra prediction, etc.) so that the bit length of the obtained coded bitstream is shortened. 
     In addition, the coding control unit  108  extracts a control parameter (decoding control information) necessary for decoding from the plural control parameters, and outputs the extracted parameter to the entropy coding unit  110 . Examples of decoding control information include pred_type, mvp_idx_lx, mvdLX, and the like. For each coding block unit CU, pred_type is set, and specifies a prediction mode (for distinguishing between inter prediction and intra prediction), and the partitioned shape of a coding block unit CU (partitioning type). The details of pred_type are described below. A motion vector predictor index for designating a candidate to be used as a motion vector predictor from a candidate list is indicated by mvp_idx_lx. A motion vector difference is indicated by mvdLX, as mentioned above. 
     EX2: Processing Operation of Moving Picture Coding Apparatus According to Comparative Example 
     Next is a description of the moving picture coding method executed by the moving picture coding apparatus  100  described above, based on  FIGS.  3  and  4 A . 
       FIG.  3    is a flowchart showing a processing procedure of a method for generating a predicted image by inter prediction coding (moving picture coding method) executed by the moving picture coding apparatus  100  described above. 
     It should be noted that a predicted image is generated per prediction block unit PU. Here, a description is given of the case where the size of a prediction block unit PU is smaller than a coding block unit CU, as an example. 
       FIG.  4 A  illustrates a relationship between the prediction block unit PU and the coding block unit CU. In  FIG.  4 A , the solid line frame indicates the coding block unit CU, and the broken line frame indicates the prediction block unit PU. The slice (picture) type is B. One slice is divided into four blocks having the same size in  FIG.  4 A . Furthermore, the upper right block is further divided into four. These blocks are coding block units CU. 
     Furthermore, in  FIG.  4 A , the coding block units CU are numbered in the order 0, 1, 2, and so on for each depth level of a tree hierarchy called “coding tree”. The numbers correspond to the coding processing order. Specifically, CU 0 , CU 10  to CU 13 , CU 2 , and CU 3  are given to the upper left block, the upper right blocks, the bottom left block, and the bottom right block, respectively. 
       FIG.  4 B  illustrates a relationship between pred_type and a coding unit tree obtained from a code string based on coding tree syntax, with regard to the coding block units CU illustrated in  FIG.  4 A . What pred_type indicates can be determined in accordance with the table illustrated in  FIG.  4 C , for example. 
       FIG.  4 C  is an interpretation table showing values of pred_type. For example, if the slice type is P or B, and the value of pred_type is 2, the prediction mode of the coding block unit CU is MODE_INTER, and the partitioned shape of the coding block unit CU is N×2N. The coding block unit CU 12  in  FIG.  4 A  corresponds to this unit, for example. In addition, for example, if the slice type is P or B, and the value of pred_type is 8, the prediction mode of the coding block unit CU is MODE_INTRA, and the partitioned shape of the coding block unit CU is 2N×2N. The coding block unit CU 0  in  FIG.  4 A  corresponds to this unit, for example. 
     The following is a description of the case where a current block to be coded is CU 12 , as an example. As mentioned above, the prediction mode of the current block CU 12  is MODE_INTER, and the current block CU 12  includes two prediction block units PU, namely, PU 0  and PU 1  (N×2N). It should be noted that in  FIG.  4 B , the area enclosed by the one-point dashed line is an area having information which is already “available” at the point in time when coding the prediction block unit PU 0  of the current block CU 12 . As illustrated in  FIG.  4 B , in Comparative Example, the coding block units CU 2  and CU 3  are not “available” at the point in time when coding the current block CU 12 . 
     Now referring to  FIG.  3   , in step S 200 , the coding control unit  108  derives a motion vector mvLX of a current block to be predicted by motion detection. 
     In step S 210 , the coding control unit  108  generates motion vector predictor candidate lists (mvpListLX) for each prediction block unit (PU unit) included in a current block to be coded (Curr_Blk) (mvpListLX generation step). It should be noted that the candidate list mvpListLX is generated for each prediction block unit PU. In addition, two candidate lists, namely, a candidate list mvpListL 0  corresponding to the prediction direction 0 and a candidate list mvpListL 1  corresponding to the prediction direction 1 are generated for each prediction block unit PU. 
       FIG.  5    illustrates the positional relationship of a current block to be predicted (currentPU, current prediction block unit PU) and adjacent blocks. In  FIG.  5   , plural adjacent blocks are divided into two block groups A and B (hereinafter, referred to as “group A” and “group B” for short in the drawings, as appropriate). The block group A includes an adjacent block A 0  on the left of the current block, and an adjacent block A 1  on the bottom-left of the current block. The block group B includes an adjacent block B 2  on the upper left of the current block, an adjacent block B 1  on the upper side of the current block, and an adjacent block B 0  on the upper right of the current block. 
     It should be noted that in  FIG.  4 A , when the prediction block unit PU 0  included in the coding block unit CU 12  is a current block to be predicted, a block corresponding to the adjacent block A 1  is the prediction block unit PU 3  included in the coding block unit CU 0 , and the block corresponding to the adjacent block A 0  is the prediction block unit PU included in the coding block unit CU 2 . 
     A description is given of motion vector predictor candidate lists generated by the coding control unit  108 , with reference to  FIGS.  6 A and  6 B .  FIG.  6 A  illustrates the candidate list mvpListL 0  for coding motion vector predictors in the prediction direction 0.  FIG.  6 B  illustrates the candidate list mvpListL 1  for coding motion vector predictors in the prediction direction 1. N is an index indicating a block group. 
       FIGS.  6 A and  6 B  show the case where the size of the candidate lists is 2, and one candidate is derived from each of the block groups A and B illustrated in  FIG.  5   . It should be noted that the case where no candidate is derived from the block groups A and B is not intended to be excluded. A detailed description of a method for deriving the candidate lists will be given below. 
     Now, referring back to  FIG.  3   , in step S 230 , the coding control unit  108  performs update processing on mvpListLX (update step). The coding control unit  108  adds an entry, duplicates a candidate included in a list, deletes a candidate, and the like as the update processing, for example. The rule for the update processing is shared between the moving picture coding apparatus  100  and a moving picture decoding apparatus  300  described below. 
     In step S 240 , the coding control unit  108  determines coding control information including the value of mvp_idx_lx for each prediction block unit PU (determination step). 
     “mvp_idx_lx” is a motion vector predictor index which indicates a motion vector predictor candidate for coding a motion vector in the prediction direction X. Here,  FIG.  7    illustrates a relationship among each candidate in the motion vector predictor candidate list mvpListLX, the motion vector mvLX, and the motion vector difference mvdLX. It should be noted that  FIG.  7    shows mvpListLX [n_mvp_idx] which is not determined to be the motion vector predictor mvpLX, for reference. The motion vector mvLX is a motion vector derived through motion detection by the coding control unit  108  in step S 200 . In the present embodiment, the coding control unit  108  determines, as a motion vector predictor, one of two motion vector predictor candidates which has the smaller difference from the motion vector mvLX. The value of mvp_idx of mvpListLX [mvp_idx] is determined to be a value of index mvp_idx_ 1 X. 
     In step S 250 , the intra/inter prediction unit  107  performs intra/inter coding on each prediction block unit PU, based on coding control information (prediction step). 
     EX2-1: Method for Generating Candidate List MvpListLX According to Comparative Example 
     Next is a detailed description of a method for generating the motion vector predictor candidate list mvpListLX, with reference to  FIGS.  8  to  10 B . 
       FIG.  8    is a flowchart showing a detailed processing procedure of mvpListLX generation step S 210 . The coding control unit  108  initializes flags (availableLXA, isScaled, availableLXB, and the like) to 0, prior to the processing below. 
     First, the coding control unit  108  performs processing of generating a first candidate for mvpListLX (S 400 ). In step S 400 , the coding control unit  108  executes processing for deriving a candidate from blocks A 0  and A 1  included in the block group A. It should be noted that there may be a case where a candidate cannot be derived from the block group A if intra prediction is used for both of the blocks A 0  and A 1 , for instance. 
     In step S 410 , the coding control unit  108  searches the block group A for a block having a motion vector which is available without scaling processing (scaling). A detailed description thereof is given below. Search is performed in the order A 0  and A 1 . The coding control unit  108  sets flag availableLXA to 1 if search succeeds. In addition, the coding control unit  108  adds a motion vector of the block obtained in the search to the candidate list mvpListLX. 
     In step S 420 , the coding control unit  108  determines whether availableLXA is 0 (whether the search has failed). 
     If the search fails (true in S 420 ), the coding control unit  108  searches the block group A (A 0 , A 1 ) for a block having an available motion vector. The search is performed in the order A 0  and A 1 . If the search has succeeded, the coding control unit  108  executes scaling processing on the motion vector of the block obtained in the search, and adds the motion vector on which scaling processing has been performed to the candidate list mvpListLx. Furthermore, the coding control unit  108  sets flag isScaled to 1. Flag isScaled is a flag indicating whether scaling processing has been performed on the block group A. Scaling processing is processing of increasing and decreasing the magnitude of a motion vector. It should be noted that Expressions 8-130 to 8-134 (see  FIG.  23 (A) ) in NPL 2 can be utilized for scaling processing. 
     Next, the coding control unit  108  performs processing of generating the second candidate for mvpListLX (S 500 ). In step S 500 , the coding control unit  108  executes processing for deriving a candidate from the block group B (B 0 , B 1 , B 2 ). It should be noted that a candidate may not be able to be derived from the block group B if intra prediction is used for all the blocks B 0 , B 1 , and B 2 , for instance. 
     Specifically, in step S 510 , the coding control unit  108  searches the block group B for a block having a motion vector which is available without scaling. The search is performed in the order B 0 , B 1 , and B 2 . The coding control unit  108  sets flag availableFlagLXB to 1 if the search succeeds. The coding control unit  108  adds the motion vector of block obtained in the search to the candidate list mvpListLX. 
     In step S 420 , the coding control unit  108  determines whether availableLXA==0, availableLXB==0, and furthermore isScaled==0. 
     If the determination result of step S 420  is “true”, the coding control unit  108  searches the block group B (B 0 , B 1 , B 2 ) for a block having an available motion vector. The search is performed in the order B 0 , B 1 , and B 2 . If the search succeeds, the coding control unit  108  executes scaling processing on the motion vector of the block obtained in the search, and adds the motion vector on which scaling processing has been performed to the candidate list mvpListLx. It should be noted that, for example, Expressions 8-135 to 8-139 (see  FIG.  23 (B) ) in NPL 2 can be utilized for scaling processing. 
     It should be noted that it is determined in step S 420  whether scaling processing has already been performed on the block group A (isScaled==0). This is for reducing the number of times scaling processing is performed. It is preferable to reduce the number of times scaling processing is performed because scaling processing requires great load. Here, the number of times scaling processing is performed is set to 1. If scaling processing is performed on the block group A, an available candidate has already been added to the candidate lists, and thus scaling processing is not to be performed on the block group B. 
     Block Group A (A 0 , A 1 ) 
     First is a description of step S 410  in  FIG.  8    (step of searching the block group A for a block having a motion vector which is available without scaling processing), based on  FIG.  9 A .  FIG.  9 A  is a flowchart showing the detailed procedure of step S 410  in  FIG.  8   . 
     In  FIG.  9 A , A[k] (k=0, 1) is a value indicating a block included in the block group A. Specifically, A[ 0 ] indicates block A 0 , and A[ 1 ] indicates block A 1 . In  FIG.  9 A , processing from step S 412  to step S 415  is executed for the blocks A 0  and A 1  (steps S 411  and S 416 ). 
     In step S 412 , the coding control unit  108  determines whether a motion vector in the prediction direction 0 of a prediction block unit PU which includes A[k] is a motion vector which is available without scaling processing. 
     Specifically, the coding control unit  108  determines whether a prediction block unit PU which includes A[k] satisfies all the followings: 
     (i) the prediction block unit PU is “available”, 
     (ii) the prediction mode thereof is not MODE_INTRA, 
     (iii) predFlagL 0  thereof is 1, and 
     (iv) refIdx thereof is equal to refIdx of PU of a current block. 
     Here, “available” in (i) indicates that the prediction block unit PU corresponding to A[k] can be utilized. It should be noted that “not available” indicates that the prediction block unit PU corresponding to A[k] cannot be utilized. Here, the case where “not available” is indicated is the case where the prediction block unit PU does not have information such as a motion vector, examples of which include the case where the prediction block unit PU is a block located, for instance, outside the boundary of a picture or a slice, and the case where the prediction block unit PU is a block which has not been coded yet, and the like. “MODE_INTRA” in (ii) indicates intra prediction is used. In the case of intra prediction, the prediction block unit PU cannot be utilized as a candidate for a motion vector predictor. “predFlagL 0 ” in (iii) is a flag indicating whether a motion vector predictor in the prediction direction 0 is to be used, and indicates that a motion vector predictor in the prediction direction 0 is to be used in the case of “1”. The determination in (iv) is, in other words, a determination as to whether a reference picture of the prediction block unit PU corresponding to A[k] is the same as a reference picture of a current block to be coded (decoded). This is equivalent to the determination as to whether the block has a motion vector which is available without performing scaling. 
     If the determination result of step S 412  is not true (in the case of “otherwise”), the determination in step S 413  is made. 
     In step S 413 , the coding control unit  108  determines a motion vector in the prediction direction 1 of a prediction block unit PU which includes A[k] is a motion vector which is available without scaling processing. This means that a determination made for motion data of block A[k] in the prediction direction 0 (a motion vector and a reference index, which also applies in the following) is also made for motion data of A[k] in the prediction direction 1. 
     If the determination result of step S 412  or the determination result of step S 413  is true, or in other words if a motion vector which is available without scaling processing is obtained in the search, the coding control unit  108  sets availableFlagLXA to 1 in step S 414 , and in step A 307 , adds, to the candidate list mvpListLX, the value of mvLX of block A[k] as it is without performing scaling processing. After that, the processing of the coding control unit  108  proceeds to step S 416 . 
     If the determination result of step S 413  is not true (if the determination results of steps S 412  and S 413  are both “otherwise”) or in other words, if a motion vector which is available without scaling processing is not obtained in the search, the processing of the coding control unit  108  proceeds to step S 416 . 
     In step S 416 , if availableFlagLXA==1 or k==1, the coding control unit  108  ends processing of step S 410 . 
     Next is a description of a processing procedure of step S 430  (step of performing scaling processing on a motion vector of the block group A) in  FIG.  8   , based on  FIG.  9 B .  FIG.  9 B  is a flowchart showing a detailed processing procedure of step S 430  in  FIG.  8   . In  FIG.  9 B , processing of steps S 432  to S 437  is executed on the blocks A 0  and A 1  (steps S 431  and S 438 ). 
     In step S 432 , the coding control unit  108  determines whether a motion vector in the prediction direction 0 of the prediction block unit PU which includes A[k] is a motion vector on which scaling processing can be performed. 
     More specifically, the coding control unit  108  makes determinations (i) to (iii) of the determinations (i) to (iv) of step S 412 . This processing is scaling processing, and thus the condition (iv) is not necessary. Therefore, the coding control unit  108  determines whether the prediction block unit PU which includes A[k] is “available” (i), the prediction mode thereof is not MODE_INTRA (ii), and prefFlagL 0  thereof is 1 (iii). 
     If the determination result of step S 432  is not true (in the case of “otherwise”), the determination of step S 433  is made. 
     In step S 433 , the coding control unit  108  determines whether a motion vector in the prediction direction 1 of a prediction block unit PU which includes A[k] is a motion vector on which scaling processing can be performed. In step S 433 , the determination made on motion data in step S 432  is also performed on motion data of A[k] in the prediction direction 1. 
     If the determination result of step S 432  or the determination result of step S 433  is true, or in other words, if a motion vector on which scaling processing can be performed is obtained in the search, the coding control unit  108  obtains information for deriving a scaling ratio (such as refIdx and List) (S 434 ). Furthermore, the coding control unit  108  sets mvLXA to the value of a motion vector mvLX of A[k], and sets refIdxLX to the reference picture index of A[k]. 
     In step S 435 , the coding control unit  108  derives a scaling ratio, and performs scaling processing. In step S 436 , the coding control unit  108  sets flag isScaled to 1 which indicates that scaling processing has been performed in the processing on the block group A. In step S 437 , the coding control unit  108  sets availableFlagLXA to 1. After that, the processing of the coding control unit  108  proceeds to step S 438 . 
     On the other hand, if the determination result of step S 433  is not true (if the determination results of steps S 432  and S 433  are both otherwise), or in other words, if a motion vector on which scaling processing can be performed is not obtained in the search, the processing of the coding control unit  108  proceeds to step S 438 . 
     In step S 438 , if availableFlagLXA==1 or k==1, the coding control unit  108  ends processing of step S 430 . 
     Block Group B (B 0 , B 1 , B 2 ) 
     First is a description of step S 510  in  FIG.  8    (a step of searching the block group B for a block having a motion vector which is available without scaling processing), based on  FIG.  10 A .  FIG.  10 A  is a flowchart showing a detailed procedure of step S 510  in  FIG.  8   . 
     It should be noted that processing shown in  FIG.  9 A  and processing shown in  FIG.  10 A  are the same except the point that blocks to be processed are different. Blocks to be processed are A 0  and A 1  in  FIG.  9 A , whereas blocks to be processed are B 0 , B 1 , and B 2  in  FIG.  10 A . Steps S 512  to S 515  in  FIG.  10 A  correspond to steps S 412  to S 415  in  FIG.  9 A , respectively. 
     Next is a description of a processing procedure of step S 530  in  FIG.  8    (step of performing scaling processing on a motion vector of the block group B), based on  FIG.  10 B .  FIG.  10 B  is a flowchart showing a detailed processing procedure of step S 530  in  FIG.  8   . 
     It should be noted that processing shown in  FIG.  9 B  and processing shown in  FIG.  10 B  are the same except the point that blocks to be processed are different, and the point that the isScaled flag is not recorded in step S 436 . Blocks to be processed are A 0  and A 1  in  FIG.  9 B , whereas blocks to be processed are B 0 , B 1 , and B 2  in  FIG.  10 B . Steps S 532  to S 536  in  FIG.  10 B  correspond to steps S 432  to S 435  and S 437  in  FIG.  9 B , respectively. 
     EX2-2: Determination of Coding Control Information 
       FIG.  11    is a flowchart showing a detailed processing procedure of step S 240  in  FIG.  3    which is a step of determining coding control information. In step S 240  in  FIG.  3   , the coding control unit  108  calculates coding efficiency achieved by using each motion vector predictor candidate, determines a motion vector predictor candidate with which coding efficiency is high, as a motion vector to be used for inter prediction. Accordingly, a value of mvp_idx_l 0  used for inter prediction and a value of mvp_idx_l 1  are determined. 
     Specifically, in step S 301 , the coding control unit  108  sets mvp_idx_l 0  to 0. Furthermore, the coding control unit  108  increments mvp_idx_l 0  by 1 after executing steps S 302  to S 308  described below. The coding control unit  108  repeatedly executes steps S 302  to S 308 . 
     In step S 302 , the coding control unit  108  determines whether availableFlagL 0  [mvp_idx_l 0 ] is 1. 
     If availableFlagL 0  [mvp_idx_l 0 ] is not 1 in step S 302  (false in S 302 ), the processing of the coding control unit  108  proceeds to step S 309 . 
     If availableFlagL 0  [mvp_idx_l 0 ] is 1 in step S 302  (true in S 302 ), the processing of the coding control unit  108  proceeds to step S 303 . 
     In step S 303 , the coding control unit  108  sets mvp_idx_l 1  to 0. Furthermore, the coding control unit  108  increments mvp_idx_l 1  by 1 after executing steps S 304  and S 305  described below. The coding control unit  108  repeatedly executes steps S 304  and S 305 . 
     In step S 304 , the coding control unit  108  determines whether availableFlagL 1  [mvp_idx_l 1 ] is 1. 
     If availableFlagL 1  [mvp_idx_l 1 ] is not 1 in step S 304  (false in S 304 ), the processing of the coding control unit  108  proceeds to step S 308 . 
     If availableFlagL 1  [mvp_idx_l 1 ] is 1 in step S 304  (true in S 304 ), the processing of the coding control unit  108  proceeds to step S 305 . 
     In step S 305 , the coding control unit  108  performs, as a trial, inter coding using a set of motion vector predictor candidates (mvpListL 0  [mvp_idx_l 0 ], mvpListL 1  [mvp_idx_l 1 ]) indicated by a set of current motion vector predictor indexes (mvp_idx_l 0 , mvp_idx_l 1 ) (hereinafter, referred to as “a set of current motion vector predictor candidates”, as necessary). 
     In step S 306 , the coding control unit  108  compares coding efficiency achieved by using a set of motion vector predictor candidates indicated by the values of a set of motion vector predictor indexes temporarily set as mvp_idx_lx (mvpListL 0  [mvp_idx_l 0 ], mvpListL 1  [mvp_idx_l 1 ]) (hereinafter, referred to as “a set of motion vector predictor candidates temporarily set”, as necessary) with coding efficiency achieved by using a set of current motion vector predictor candidates. 
     In step S 306 , if the coding efficiency achieved using the set of motion vector predictor candidates temporarily set is higher than the coding efficiency achieved using the set of current motion vector predictor candidates (N in S 306 ), the processing of the coding control unit  108  proceeds to step S 308 . 
     In step S 306 , if the coding efficiency achieved using the set of current motion vector predictor candidates is higher than the coding efficiency achieved using the set of motion vector predictor candidates temporarily set (Y in S 306 ), the processing of the coding control unit  108  proceeds to step S 307 , and the coding control unit  108  sets the set of motion vector predictor indexes mvp_idx_lx (mvp_idx_l 0 , mvp_idx_l 1 ) to the values of the current set (mvp_idx_l 0 , mvp_idx_l 1 ). It should be noted that if no value is set in the set mvp_idx_lx of motion vector predictor indexes (mvp_idx_l 0 , mvp_idx_l 1 ), the coding control unit  108  sets mvp_idx_lx to the values of the current set (mvp_idx_l 0 , mvp_idx_l 1 ). 
     In step S 308 , the coding control unit  108  determines whether mvpListL 1  [mvp_idx_l 1 ] is the last candidate of the candidate list ( FIG.  11    shows “Processing for mvp_idx_l 1  is completed?). For example, in the case of the candidate list mvpListL 1  illustrated in  FIG.  6 B , the size of the candidate list is 2, and thus it is determined that mvpListL 1  [mvp_idx_l 1 ] is the last candidate if mvp_idx_l1==1 (=candidate list size−1). If it is determined that mvpListL 1  [mvp_idx_l 1 ] is not the last candidate of the candidate list, the processing of the coding control unit  108  returns to step S 303 , and the coding control unit  108  increments mvp_idx_l 1  by 1 (S 303 ). 
     If it is determined in step S 308  that mvpListL 1  [mvp_idx_l 1 ] is the last candidate of the candidate list, the processing of the coding control unit  108  proceeds to step S 309 . 
     In step S 309 , the coding control unit  108  determines whether mvpListL 0  [mvp_idx_l 0 ] is the last candidate of the candidate list (“Processing for mvp_idx_l 0  is completed?). For example, in the case of the candidate list mvpListL 0  illustrated in  FIG.  6 A , the size of the candidate list is 2, and thus if mvp_idx_l0==1 (=candidate list size−1), the coding control unit  108  determines that mvpListL 0  [mvp_idx_l 0 ] is the last candidate. If the coding control unit  108  determines that mvpListL 0  [mvp_idx_l 0 ] is not the last candidate of the candidate list, the processing of the coding control unit  108  returns to step S 301 , and the coding control unit  108  increments mvp_idx_l 0  by 1 (S 301 ). 
     In step S 309 , if the coding control unit  108  determines that mvpListL 0  [mvp_idx_l 0 ] is the last candidate of the candidate list, the processing thereof proceeds to step S 310 . 
     In step S 310 , the coding control unit  108  determines mvp_idx_lx (mvp_idx_l 0 , mvp_idx_l 1 ) as a set of motion vector predictor indexes. 
     The following is a brief description of the case of  FIGS.  6 A and  6 B . 
     The coding control unit  108  sets mvp_idx_l 0  to 0 when step S 301  is executed in the first loop. In step S 302 , as illustrated in FIG.  6 A, the coding control unit  108  determines that availableFlagLXA is 1, and the processing thereof proceeds to step S 303 . 
     The coding control unit  108  sets mvp_idx_l 1  to 0 when step S 303  is executed in the first loop. In step S 304 , the processing of the coding control unit  108  proceeds to step S 305  since availableFlagLXB is 1 as illustrated in  FIG.  6 B . 
     In step S 305 , the coding control unit  108  performs, as a trial, inter coding using a current set (mvpListL 0  [0], mvpListL 0  [0]). In step S 306 , the coding control unit  108  has not executed inter coding as a trail before, and thus the processing thereof proceeds to step S 307 , and the coding control unit  108  sets mvp_idx_lx to (0, 0). 
     In step S 308 , the processing of the coding control unit  108  proceeds to step S 309  since there is only one mvp_idx_l 1  as illustrated in  FIG.  6 B , and thus processing is completed. In step S 309  in the first loop, the coding control unit  108  determines that processing is not completed since mvp_idx_l 0  takes two values, namely, 0 and 1 as illustrated in  FIG.  6 A . The processing of the coding control unit  108  returns to step S 301 , and the coding control unit  108  sets mvp_idx_l 0  to 1 and starts the second loop. 
     When step S 301  is executed in the second loop, the coding control unit  108  sets mvp_idx_l 0  to 1. In step S 302 , as illustrated in  FIG.  6 A , the coding control unit  108  determines that availableFlagLXB is 1, and the processing thereof proceeds to step S 303 . 
     When step S 303  which is the first step in the second loop is executed, the coding control unit  108  sets mvp_idx_l 1  to 0. In step S 304 , the processing of the coding control unit  108  proceeds to step S 305  since availableFlagLXB is 1 as illustrated in  FIG.  6 B . 
     In step S 305 , the coding control unit  108  performs inter coding as a trial, using a current set (mvpListL 0  [1], mvpListL 0  [0]). In step S 306 , the coding control unit  108  compares coding efficiency achieved using (mvpListL 0  [0], mvpListL 0  [0]) which have been used to perform inter coding as a trial before with coding efficiency achieved using the current set (mvpListL 0  [1], mvpListL 0  [0]). Here, if coding efficiency achieved using (mvpListL 0  [0], mvpListL 0  [0]) used before is higher, the processing of the coding control unit  108  proceeds to step S 308 . 
     In step S 308 , the processing of the coding control unit  108  proceeds to step S 309  since there is only one mvp_idx_l 1  as illustrated in  FIG.  6 B , and thus processing is completed. In step S 309  in the second loop, mvp_idx_l 0  takes two values, namely, 0 and 1 as illustrated in  FIG.  6 A , and processing has been executed for each, the coding control unit  108  determines that processing is completed, and the processing thereof proceeds step S 310 . 
     In step S 310 , the coding control unit  108  determines (0, 0) to which mvp_idx_lx is set, as a set of values of mvp_idx_lx. 
     EX2-3: Intra Inter Coding 
       FIG.  12    is a flowchart illustrating a detailed processing procedure of step S 250  in  FIG.  3   . In step S 250  in  FIG.  3   , intra/inter coding is executed on a moving picture indicated by an input image signal, using coding control information, decoding control information, and the like obtained by the coding control unit  108 . 
     Specifically, in step S 252 , the intra/inter prediction unit  107  generates a predicted image of a current block to be coded, based on motion vector mvLX, and outputs a predicted image signal indicating the generated predicted image. The difference unit  101  subtracts the predicted image signal from an input image signal to generate a residual signal. The transform unit  102  converts the residual signal from an image domain into a frequency domain, and the quantization unit  103  quantizes the residual signal converted into the frequency domain to generate a quantized residual signal. The entropy coding unit  110  codes the quantized residual signal. 
     In step S 254 , the entropy coding unit  110  codes a set of motion vector predictor indexes mvp_idx_lx (mvp_idx_l 0 , mvp_idx_l 1 ). The entropy coding unit  110  codes mvp_idx_lx (0, 0) in the case of  FIGS.  6 A and  6 B  described in EX2-2, for example. 
     In step S 256 , the entropy coding unit  110  codes a motion vector difference mvdLX. 
     The entropy coding unit  110  generates and outputs a coded bitstream which includes the quantized residual signal, the set mvp_idx_lx of motion vector predictor indexes (mvp_idx_l 0 , mvp_idx_l 1 ), and the motion vector difference mvdLX which have been coded. 
       FIG.  13    illustrates a problem of mvpListLX generation processing (see  FIGS.  8  to  10 B , and EX 2-1) in Comparative Example. 
     In  FIG.  13   , the horizontal double line is a symbol representing parallel processing, and processing between the horizontal double lines is parallel processing. 
     In Comparative Example above, as illustrated in  FIG.  13   , it is possible to shorten a processing time period by performing processing of obtaining a motion vector predictor candidate from the block group A (step S 400  in  FIG.  8   ) and processing of obtaining a motion vector predictor candidate from the block group B (step S 500  in  FIG.  8   ) in parallel. 
     Here, in Comparative Example above, as illustrated in  FIG.  13   , whether scaling processing has been executed on the block group A in S 436  in step S 430  is one determination condition in step S 520 . 
     This is to prevent scaling processing from being executed on the block group B if scaling processing is already executed on the block group A, in order that scaling processing which requires great processing load is to be performed once, as mentioned above. 
     Accordingly, in Comparative Example above, step S 500  which is processing on the block group B has a problem that it is necessary to wait for the completion of step S 400  which is processing on the block group A (in particular, S 436 ), in order to execute processing of step S 520 . 
     In view of this, an image decoding method according to one aspect of the present disclosure is a moving picture decoding method for decoding a current block included in a bitstream, using a motion vector predictor used when decoding a motion vector of the current block, the method including: (a) obtaining one or more motion vector predictor candidates which are candidates for the motion vector predictor; (b) decoding a coded index for identifying one of the one or more motion vector predictor candidates, the coded index being added to the bitstream; and (c) selecting, based on the decoded index, the motion vector predictor to be used for decoding the current block from among the one or more motion vector predictor candidates, wherein step (a) includes: (a1) generating a motion vector predictor candidate, based on plural motion vectors of plural first adjacent blocks adjacent to the current block in a first direction; and (a2) generating a motion vector predictor candidate, based on plural motion vectors of plural second adjacent blocks adjacent to the current block in a second direction, and step (a2) includes: (i) determining whether the plural first adjacent blocks include one or more inter-predicted blocks; and (ii) searching for a motion vector to be made available by scaling processing from among the plural motion vectors of the plural second adjacent blocks when it is determined in step (i) that the plural first adjacent blocks do not include an inter-predicted block, and generating, when the motion vector is obtained in the search, one of the one or more motion vector predictor candidates by executing scaling processing on the motion vector obtained in the search. 
     In addition, for example, in step (a2), when it is determined in step (i) that the plural first adjacent blocks include one or more inter-predicted blocks, it may be determined whether all the one or more of the plural first adjacent blocks determined to be inter-predicted blocks are blocks each located at a picture boundary or a slice boundary, and step (ii) may be executed when all the one or more of the plural first adjacent blocks determined to be inter-predicted blocks are blocks each located at the picture boundary or the slice boundary. 
     In addition, for example, step (a2) may further include (iii) searching for a motion vector available without scaling processing from among the plural motion vectors of the plural second adjacent blocks, and determining, when a motion vector available without scaling processing is obtained in the search, the motion vector obtained in the search as one of the one or more motion vector predictor candidates, and step (i) may be executed when a motion vector available without scaling processing is not obtained in the search. 
     In addition, for example, in step (iii), it may be determined whether a reference picture of the current block is the same as a reference picture of each of the plural second adjacent blocks, and among the plural second adjacent blocks, a second adjacent block determined to have the same reference picture may be obtained in the search as a motion vector available without scaling processing. 
     In addition, for example, step (a1) may include: (i) searching for a motion vector available without scaling processing from among the plural motion vectors of the plural first adjacent blocks, and determining, when a motion vector available without scaling processing is obtained in the search, the motion vector obtained in the search as one of the one or more motion vector predictor candidates; (ii) determining whether a motion vector available without scaling processing is obtained in the search from the plural first adjacent blocks; and (iii) searching, when it is determined that a motion vector available without scaling processing is not obtained in the search from the plural first adjacent blocks, for a motion vector to be made available by scaling processing from among the plural motion vectors of the plural first adjacent blocks, and generating, when the motion vector is obtained in the search, one of the one or more motion vector predictor candidates by executing scaling processing on the motion vector obtained in the search. 
     In addition, for example, step (a1) and step (a2) may be executed in parallel. 
     An image coding method according to one aspect of the present disclosure is a moving picture coding method for coding a current block to generate a bitstream, using a motion vector predictor used when coding a motion vector of the current block, the method including: (a) obtaining one or more motion vector predictor candidates which are candidates for the motion vector predictor; (b) selecting the motion vector predictor to be used for coding the motion vector of the current block from among the one or more motion vector predictor candidates; and (c) coding an index for identifying the selected motion vector predictor, and adding the coded index to the bitstream, wherein step (a) includes: (a1) generating a motion vector predictor candidate, based on plural motion vectors of plural first adjacent blocks adjacent to the current block in a first direction; and (a2) generating a motion vector predictor candidate, based on plural motion vectors of plural second adjacent blocks adjacent to the current block in a second direction, and step (a2) includes: (i) determining whether the plural first adjacent blocks include one or more inter-predicted blocks; and (ii) searching for a motion vector to be made available by scaling processing from among the plural motion vectors of the plural second adjacent blocks when it is determined in step (i) that the plural first adjacent blocks do not include an inter-predicted block, and generating, when the motion vector is obtained in the search, one of the one or more motion vector predictor candidates by executing scaling processing on the motion vector obtained in the search. 
     In addition, for example, in step (a2), when it is determined in step (i) that the plural first adjacent blocks include one or more inter-predicted blocks, it may be determined whether all the one or more of the plural first adjacent blocks determined to be inter-predicted blocks are blocks each located at a picture boundary or a slice boundary, and step (ii) may be executed when all the one or more of the plural first adjacent blocks determined to be inter-predicted blocks are blocks each located at the picture boundary or the slice boundary. 
     In addition, for example, step (a2) may further include (iii) searching for a motion vector available without scaling processing from among the plural motion vectors of the plural second adjacent blocks, and determining, when a motion vector available without scaling processing is obtained in the search, the motion vector obtained in the search as one of the one or more motion vector predictor candidates, and step (i) may be executed when a motion vector available without scaling processing is not obtained in the search. 
     In addition, for example, in step (iii), it may be determined whether a reference picture of the current block is the same as a reference picture of each of the plural second adjacent blocks, and among the plural second adjacent blocks, a second adjacent block determined to have the same reference picture may be obtained in the search as a motion vector available without scaling processing. 
     In addition, for example, step (a1) may include: (i) searching for a motion vector available without scaling processing from among the plural motion vectors of the plural first adjacent blocks, and determining, when a motion vector available without scaling processing is obtained in the search, the motion vector obtained in the search as one of the one or more motion vector predictor candidates; (ii) determining whether a motion vector available without scaling processing is obtained in the search from the plural first adjacent blocks; and (iii) searching, when it is determined that a motion vector available without scaling processing is not obtained in the search from the plural first adjacent blocks, for a motion vector to be made available by scaling processing from among the plural motion vectors of the plural first adjacent blocks, and generating, when the motion vector is obtained in the search, one of the one or more motion vector predictor candidates by executing scaling processing on the motion vector obtained in the search. 
     In addition, for example, step (a1) and step (a2) may be executed in parallel. 
     An image decoding apparatus according to one aspect of the present disclosure is a moving picture decoding apparatus which decodes a current block included in a bitstream, using a motion vector predictor used when decoding a motion vector of the current block, the apparatus including: a motion vector predictor candidate obtaining unit configured to obtain one or more motion vector predictor candidates which are candidates for the motion vector predictor; a decoding unit configured to decode a coded index for identifying one of the one or more motion vector predictor candidates, the coded index being added to the bitstream; and a selection unit configured to select, based on the decoded index, the motion vector predictor to be used for decoding the current block from among the one or more motion vector predictor candidates, wherein the motion vector predictor candidate obtaining unit is configured to execute: first candidate generation processing of generating a motion vector predictor candidate, based on plural motion vectors of plural first adjacent blocks adjacent to the current block in a first direction; and second candidate generation processing of generating a motion vector predictor candidate, based on plural motion vectors of plural second adjacent blocks adjacent to the current block in a second direction, and in the second candidate generation processing, the motion vector predictor candidate obtaining unit is configured to: determine whether the plural first adjacent blocks include one or more inter-predicted blocks; and search for a motion vector to be made available by scaling processing from among the plural motion vectors of the plural second adjacent blocks when the motion vector predictor candidate obtaining unit determines that the plural first adjacent blocks do not include an inter-predicted block, and generate, when the motion vector predictor candidate obtaining unit obtains the motion vector in the search, one of the one or more motion vector predictor candidates by executing scaling processing on the motion vector obtained in the search. 
     An image coding apparatus according to one aspect of the present disclosure is a moving picture coding apparatus which codes a current block to generate a bitstream, using a motion vector predictor used when coding a motion vector of the current block, the apparatus including: a motion vector predictor candidate obtaining unit configured to obtain one or more motion vector predictor candidates which are candidates for the motion vector predictor; a selection unit configured to select the motion vector predictor to be used for coding the motion vector of the current block from among the one or more motion vector predictor candidates; and a coding unit configured to code an index for identifying the selected motion vector predictor, and add the coded index to the bitstream, wherein the motion vector predictor candidate obtaining unit is configured to execute: first candidate generation processing of generating a motion vector predictor candidate, based on plural motion vectors of plural first adjacent blocks adjacent to the current block in a first direction; and second candidate generation processing of generating a motion vector predictor candidate, based on plural motion vectors of plural second adjacent blocks adjacent to the current block in a second direction, and in the second candidate generation processing, the motion vector predictor candidate obtaining unit is configured to: determine whether the plural first adjacent blocks include one or more inter-predicted blocks; and search for a motion vector to be made available by scaling processing from among the plural motion vectors of the plural second adjacent blocks when the motion vector predictor candidate obtaining unit determines that the plural first adjacent blocks do not include an inter-predicted block, and generate, when the motion vector predictor candidate obtaining unit obtains the motion vector in the search, one of the one or more motion vector predictor candidates by executing scaling processing on the motion vector obtained in the search. 
     An image coding and decoding apparatus according to one aspect of the present disclosure includes the above moving picture decoding apparatus and the above moving picture coding apparatus. 
     It should be noted that these general and specific aspects may be implemented using a system, a method, an integrated circuit, a computer program, a computer-readable recording medium such as a CD-ROM, or any combination of systems, methods, integrated circuits, computer programs or recording media. 
     The following is a specific description of a moving picture coding apparatus and a moving picture decoding apparatus according to an aspect of the present disclosure, with reference to the drawings. 
     Each of the exemplary embodiments described below shows a specific example of the present disclosure. Numerical values, shapes, material, constituent elements, the arranged positions and connection configuration of the constituent elements, steps, the order of the steps, and so on described in the following embodiments are mere examples. Therefore, among the constituent elements in the following exemplary embodiments, constituent elements not recited in any one of the independent claims are described as arbitrary constituent elements. 
     Embodiment 1 
     A description is given of a moving picture coding apparatus and a moving picture coding method according to the present embodiment, based on  FIG.  14   . 
     It should be noted that the configuration of the moving picture coding apparatus according to the present embodiment is the same as the configuration of the moving picture coding apparatus  100  according to Comparative Example illustrated in  FIG.  2   . 
     In addition, the present embodiment describes the case using an example in which the relationship between a coding block unit CU and a prediction block unit PU is the same as the relationship between the coding block unit CU and the prediction block unit PU in Comparative Example illustrated in  FIG.  4 A , to facilitate description. 
     1-1: Moving Picture Coding Method According to Embodiment 1 
     A description is given of processing operation (moving picture coding method) of the moving picture coding apparatus  100  according to the present embodiment, based on  FIG.  14   .  FIG.  6    illustrates a processing procedure of the moving picture coding apparatus  100  according to the present embodiment. 
     It should be noted that in  FIG.  14   , processing of steps S 410  and S 430  on a block group A, and steps S 510  and S 530  on a block group B are the same as processing in Comparative Example above (see  FIGS.  8  to  10 B ). 
     It should be noted that in the present embodiment, a predicted image is generated per prediction block unit PU, as with Comparative Example. In addition, the present embodiment describes the case as an example in which the size of prediction block unit PU is smaller than that of the coding block unit CU as with Comparative Example. In addition, the relationship between the coding block unit CU and the prediction block unit PU in the present embodiment is the same as the relationship between the coding block unit CU and the prediction block unit PU in Comparative Example illustrated in  FIGS.  4 A to  4 C . 
     In the moving picture coding method according to the present embodiment illustrated in  FIG.  14   , determination processing of step S 620  is executed, instead of determination processing of step S 520 , in contrast to Comparative Example illustrated in  FIG.  13   . 
     Specifically, as illustrated in  FIG.  14   , in step S 400 , a coding control unit  108  executes processing of searching the block group A for a motion vector which is available without scaling processing (S 410 ), and executes scaling processing (S 430 ) on a block included in the block group A if a motion vector which is available without scaling processing is not obtained in the search (true in S 420 ). 
     Furthermore, the coding control unit  108  executes step S 600  in parallel with step S 400  described above, as illustrated in  FIG.  14   . In step S 600 , first, the coding control unit  108  executes processing of searching the block group B for a motion vector which is available without scaling processing (S 510 ). 
     In step S 620 , the coding control unit  108  determines (1) whether availableFlavLXB==0 (not shown in  FIGS.  14   ), and (2) whether “any block in the block group A (A 0 , A 1 ) is an INTER block”. In other words, in step S 620 , when (1) availableFlavLXB==0, and furthermore a block whose prediction mode is MODE_INTER is included in the block group A, the result is determined to be true. 
     If (1) availableFlavLXB==0, and furthermore the prediction mode of A 0  (block on the bottom left of  FIG.  5   ) or A 1  (block on the left of  FIG.  5   ) is MODE_INTER as a result of the determination (true in S 620 ), the coding control unit  108  ends step S 600  without executing processing of S 530  (scaling processing on the block group B). 
     This is based on an assumption that “if the prediction mode of any block in the block group A adjacent on the left of a current block to be predicted is MODE_INTER, a possibility that scaling processing is used is high”, and thus scaling processing is not to be performed on the block group B if the prediction mode of any block in the block group A is MODE_INTER. 
     In this way, the processing result of step S 400  is not used in step S 620 . In other words, steps S 400  and S 600  do not depend on each other. Accordingly, the moving picture coding apparatus  100  can execute in parallel step S 400  which is processing on the block group A and step S 600  which is processing on the block group B, and increase the processing speed without increasing processing load (without increasing the number of times scaling processing is performed). 
     Embodiment 2 
     A description is given of a moving picture decoding apparatus and a moving picture decoding method according to the present embodiment, based on  FIG.  15   . The moving picture decoding apparatus according to the present embodiment accepts a coded bitstream from the moving picture coding apparatus  100  according to Embodiment 1, generates decoded image signals by decoding a coded bitstream, and outputs the signals in the display order. 
     2-1: Configuration of Moving Picture Decoding Apparatus According to Embodiment 2 
     A description is given of a configuration of a moving picture decoding apparatus  300  according to the present embodiment, based on  FIG.  15   .  FIG.  15    is a block diagram illustrating the configuration of the moving picture decoding apparatus  300 . 
     As illustrated in  FIG.  15   , the moving picture decoding apparatus  300  includes an entropy decoding unit  301 , an inverse quantization unit  302 , an inverse transform unit  303 , an addition unit  304 , an intra/inter prediction unit  305 , a decoding control unit  306 , and a memory  307 . 
     The entropy decoding unit  301  performs variable-length decoding processing on an inputted coded bitstream, and thereby generates a quantized residual signal (quantization coefficient), picture type information, a prediction direction flag, and a motion vector difference mvdLX. The entropy decoding unit  301  performs variable-length decoding processing on a motion vector predictor index. Furthermore, the entropy decoding unit  301  outputs decoding control information to the decoding control unit  306  described below. Here, decoding control information includes a motion vector predictor index mvp_idx_lx (mvp_idx_l 0 , mvp_idx_l 1 ) and a motion vector difference mvdLX (mvdL 0 , mvdL 1 ). 
     The inverse quantization unit  302  performs inverse quantization processing on a quantization coefficient (quantized residual signal) obtained by variable-length decoding processing. The inverse transform unit  303  outputs a reconstructed residual signal (prediction error data) by converting a transform coefficient obtained by inverse quantization processing from a frequency domain into an image domain. 
     In the memory  307 , decoded image data indicated by decoded image signals outputted from the addition unit  304  described below is stored on a block-by-block basis and a frame-by-frame basis. 
     The intra/inter prediction unit  305  performs inter-prediction using decoded image data in a frame unit stored in the memory  307  or using decoded image data in a block unit, thereby generating a predicted image signal of a current block to be decoded. 
     The decoding control unit  306  derives motion vector predictor candidate lists mvpListL 0  and mvpListL 1 , and selects, from the derived motion vector predictor candidate lists, a motion vector predictor mvLX to be used for inter prediction, based on the motion vector predictor index (mvp_idx_l 0 , mvp_idx_l 1 ). Furthermore, the decoding control unit  306  calculates the motion vector mvLX of a current block to be decoded, using the motion vector predictor mvpLX and the motion vector difference mvdLX (mvdL 0 , mvdL 1 ). Then, if the prediction mode of a current block to be predicted is MODE_INTER, the decoding control unit  306  causes the intra/inter prediction unit  305  to generate an inter-predicted image using the calculated motion vector mvLX. 
     Finally, the addition unit  304  generates a decoded image signal by adding a reconstructed residual signal and a predicted image signal. 
     2-2: Moving Picture Decoding Method according to in Embodiment 2 
     A description is given of the processing operation (moving picture decoding method) of the moving picture decoding apparatus  300  according to the present embodiment, based on  FIG.  16   .  FIG.  16    is a flowchart showing a processing procedure of the moving picture decoding method according to the present embodiment. 
     It should be noted that in the present embodiment, a predicted image is generated per prediction block PU, as with Embodiment 1. The present embodiment describes the case as an example in which the size of a prediction block unit PU is smaller than that of a coding block unit CU, as with Embodiment 1. In addition, the relationship between a coding block unit CU and a prediction block unit PU in the present embodiment is the same as that in Comparative Example illustrated in  FIG.  4 A . 
     The following is a description of the case where a current block to be decoded is CU 12 , as an example. As illustrated in  FIGS.  4 B and  4 C , the prediction mode of the current block CU 12  is MODE_INTER, and the current block CU 12  includes two prediction block units PU, namely, PU 0  and PU 1  (N×2N). It should be noted that as described in Comparative Example, in  FIG.  4 B , the area enclosed by the one-point dashed line is an area having information which is already “available” at the point in time when coding the prediction block unit PU 0  of the current block CU 12 . As illustrated in  FIG.  4 B , in Comparative Example, coding block units CU 2  and CU 3  are not “available” when coding the current block CU 12 . 
     Referring to  FIG.  16   , in step S 1010 , the decoding control unit  306  performs processing of generating a candidate list mvpListX of motion vector predictors. This processing corresponds to the mvpListX generation processing of step S 210  illustrated in  FIG.  3    performed by the moving picture coding apparatus  100  according to Embodiment 1 (Comparative Example 1). More specifically, the decoding control unit  306  performs the same processing as the processing illustrated in  FIG.  14    executed by the moving picture coding apparatus  100 , which will be described in detailed below. 
     In step S 1020 , the decoding control unit  306  performs update processing on mvpListLX (update step). This processing corresponds to the update processing of step S 230  illustrated in  FIG.  3    performed by the moving picture coding apparatus  100  according to Embodiment 1 (Comparative Example 1). 
     In step S 1030 , the entropy decoding unit  301  extracts a motion vector predictor index mvp_idx_lx from a coded bitstream. 
     In step S 1040 , the entropy decoding unit  301  extracts a motion vector difference mvdLX from the coded bitstream. 
     In step S 1050 , the decoding control unit  306  reconstructs a motion vector in the prediction direction X. Specifically, the decoding control unit  306  identifies a motion vector predictor mvpListX [mvp_idx_lx] from the candidate list mvpListX of motion vector predictors generated in step S 1020 , using the motion vector predictor index mvp_idx_lx extracted by the entropy decoding unit  301 . As indicated by Expression 1, the decoding control unit  306  adds the motion vector difference mvdLX and the motion vector predictor mvpListX [mvp_idx_lx], thereby obtaining the motion vector mvLX. 
       mvLX=mvpListLX[mvp_idx_lx]+mvdLX  (Expression 1)
 
     In step S 1060 , the moving picture decoding apparatus  300  generates a predicted image signal using the motion vector mvLX reconstructed by the intra/inter prediction unit  305 , and generates a decoded image signal by the addition unit  304  adding a reconstructed residual signal and a predicted image signal. 
       FIG.  17    is a flowchart illustrating a detailed processing procedure of the mvpListLX creation step which is step S 1010  in  FIG.  16   . 
     In step S 400 , the decoding control unit  306  creates an entry from a block group A (A 0 , A 1 ). Specifically, in step S 401 , the decoding control unit  306  searches the block group A (A 0 , A 1 ) for a motion vector which is available without scaling processing. If a motion vector which is available without scaling processing is not obtained in the search (true in S 420 ), the decoding control unit  306  searches for an available motion vector, and performs scaling processing on the motion vector obtained in the search (S 430 ). It should be noted that processing of step S 400  is the same processing as step S 400  performed by the coding control unit  108  of the moving picture coding apparatus  100 . 
     In step S 800 , the decoding control unit  306  creates an entry from the block group B (B 0 , B 1 , B 2 ). 
     Specifically, in step S 510 , the decoding control unit  306  searches the block group B (B 0 , B 1 , B 2 ) for a motion vector which is available without scaling processing. Processing of step S 510  is the same processing as step S 510  performed by the coding control unit  108  of the moving picture coding apparatus  100 . 
     In step S 820 , the decoding control unit  306  determines whether availableFlavLXB==0, and furthermore the prediction mode of any block in the block group A is MODE_INTER. More specifically, if the decoding control unit  306  executes steps S 400  and S 800  in parallel (sequentially), the decoding control unit  306  determines in step S 510  whether availableFlag is not set (availableFlagLXB is still set to 0) and furthermore whether “the prediction mode of any of blocks A 0 , A 1 , and so on in the block group A is MODE_INTER” returns true, which is a determination condition used instead of the isSca led determination. 
     If availableFlavLXB==0, and furthermore the prediction mode of any one block in the block group A is MODE_INTER (true in S 820 ), the decoding control unit  306  ends the mvpListLX creation step without performing scaling processing. 
     If availableFlavLXB==0, and furthermore the prediction mode of none of the blocks in the block group A is MODE_INTER (false in S 820 ), the decoding control unit  306  searches for an available motion vector, and performs scaling processing on the motion vector obtained in the search (S 530 ). The processing of step S 530  is the same as processing of step S 530  performed by the coding control unit  108  of the moving picture coding apparatus  100 . 
       FIG.  18    sequentially illustrates the mvpListLX creation step which is step S 1010 . It should be noted that the steps in  FIG.  18    (S 410 , S 420 , S 430 , S 510 , S 820 , S 530 ) are the same as the steps in  FIG.  17    (S 410 , S 420 , S 430 , S 510 , S 820 , S 530 ). 
     As is clear from  FIG.  18   , in the moving picture decoding apparatus  300  according to the present embodiment, what is determined in step S 820  performed in the processing on the block group B does not depend on the result of processing of step S 1010  on the block group A. Thus, it is possible to execute the following steps in parallel:
         S 400 : generation of an entry based on the block group A (A 0 , A 1 ); and   S 800 : generation of an entry based on the block group B (A 0 , A 1 ).       

     Example 1 of Determination (Common Points of Moving Picture Coding Apparatus  100  and Moving Picture Decoding Apparatus  300 ) 
       FIG.  19    illustrates the determination results of step S 620  in  FIG.  14    and step S 820  in  FIG.  18    obtained when a current block to be predicted (a current block to be coded, a current block to be decoded) is PU 0  (see  FIG.  4 A ). As described above, it is determined in step S 620  in  FIG.  14    and step S 820  in  FIG.  18    whether any of the blocks A 0  and A 1  in the block group A is an INTER block. 
     In the case of  FIG.  19   , an adjacent block A 0  is not available, and the prediction mode thereof is not MODE_INTER. In addition, although an adjacent block A 1  is available, the prediction mode thereof is MODE_INTRA and not MODE_INTER. 
     Therefore, in the above determination step, the result is determined to be false since the prediction mode of both the adjacent blocks A 0  and A 0  is not MODE_INTER in the case of  FIG.  19   . 
     Example 2 of Determination (Common Points of Moving Picture Coding Apparatus  100  and Moving Picture Decoding Apparatus  300 ) 
       FIG.  20    illustrates the determination results of step S 620  in  FIG.  14    and step S 820  in  FIG.  18    obtained when a current block to be predicted is PU 1 . 
     In the case of  FIG.  20   , in regard with the adjacent block A 0 , CU 3  is still not available. In addition, the prediction mode of the adjacent block A 1  is MODE_INTER. 
     Therefore, in the above determination step, the result is determined to be true since the prediction mode of the adjacent block A 1  is MODE_INTER in the case of  FIG.  20   . 
     Effects and Others 
     According to the moving picture coding method and the coding apparatus according to Embodiment 1 and the moving picture decoding method and the moving picture decoding apparatus according to Embodiment 2, when generating mvpListLX (step S 620  in  FIG.  14   , step S 820  in  FIG.  18   ), the determination as to whether scaling calculation has been performed on the block group A can be omitted in the determination as to whether scaling processing is to be performed on the block group B. In other words, the coding control unit  108  and the decoding control unit  306  can determine whether to perform scaling processing on the block group B, without using the result of processing on the block group A. 
     In addition, before creating the candidate list mvpListLX, if a determination is just made as to whether the block group A includes an INTER block, motion vector predictor candidates can be calculated from the block groups A and B in parallel ( FIGS.  14  and  18   ). 
     It should be noted that although it is determined in steps S 620  and S 820  whether the prediction mode of any one of blocks A 0  and A 1  in the block group A is MODE_INTER, the embodiments are not limited to this. In steps S 620  and S 820 , for example, a determination may be made as to whether none of the followings are satisfied: (1) the prediction mode of a block is MODE_INTRA, (2) a block is at a slice or picture boundary, and (3) a block is an unprocessed block (uncoded block or undecoded block). 
     In addition, in Embodiments 1 and 2, although steps S 620  and S 820  are executed after step S 510 , the embodiments are not limited to this. Steps S 620  and S 820  may be executed, as step S 840 , before executing the processing in parallel, or specifically, before executing steps S 410  and S 510 , as illustrated in  FIG.  21   , for example. It should be noted that the order of determination (order of an AND operation and an OR operation) is not limited to Embodiments 1 and 2 above and the order of logical operation according to which the result of determination is equal is included in the present disclosure. 
     As described above, according to the moving picture coding method according to Embodiment 1 and the moving picture decoding method according to Embodiment 2, in steps S 620  and S 820 , processing on the block group B can be executed without using the result of processing on the block group A, and processing on the block group A and processing on the block group B can be performed in parallel. 
     Embodiment 3 
       FIG.  23    is a flowchart illustrating another embodiment of the moving picture coding method according to Embodiment 1 and the moving picture decoding method according to Embodiment 2. 
     Although in Embodiments 1 and 2, it is determined whether scaling processing is to be allowed in the processing on the block group B, based on the result of determination as to whether any of the blocks (A0, A1) in the block group A is an INTER block, scaling processing on the block group B is completely inhibited in the present embodiment. 
     In this way, it is also possible to resolve dependency by not performing steps S 620 , S 820 , and S 530 . 
     Embodiment 4 
     The processing described in each of embodiments can be simply implemented in an independent computer system, by recording, in a recording medium, a program for implementing the configurations of the moving picture coding method (image coding method) and the moving picture decoding method (image decoding method) described in each of embodiments. The recording media may be any recording media as long as the program can be recorded, such as a magnetic disk, an optical disk, a magnetic optical disk, an IC card, and a semiconductor memory. 
     Hereinafter, the applications to the moving picture coding method (image coding method) and the moving picture decoding method (image decoding method) described in each of embodiments and systems using thereof will be described. The system has a feature of having an image coding and decoding apparatus that includes an image coding apparatus using the image coding method and an image decoding apparatus using the image decoding method. Other configurations in the system can be changed as appropriate depending on the cases. 
       FIG.  24    illustrates an overall configuration of a content providing system ex 100  for implementing content distribution services. The area for providing communication services is divided into cells of desired size, and base stations ex 106 , ex 107 , ex 108 , ex 109 , and ex 110  which are fixed wireless stations are placed in each of the cells. 
     The content providing system ex 100  is connected to devices, such as a computer ex 111 , a personal digital assistant (PDA) ex 112 , a camera ex 113 , a cellular phone ex 114  and a game machine ex 115 , via the Internet ex 101 , an Internet service provider ex 102 , a telephone network ex 104 , as well as the base stations ex 106  to ex 110 , respectively. 
     However, the configuration of the content providing system ex 100  is not limited to the configuration shown in  FIG.  24   , and a combination in which any of the elements are connected is acceptable. In addition, each device may be directly connected to the telephone network ex 104 , rather than via the base stations ex 106  to ex 110  which are the fixed wireless stations. Furthermore, the devices may be interconnected to each other via a short distance wireless communication and others. 
     The camera ex 113 , such as a digital video camera, is capable of capturing video. A camera ex 116 , such as a digital camera, is capable of capturing both still images and video. Furthermore, the cellular phone ex 114  may be the one that meets any of the standards such as Global System for Mobile Communications (GSM) (registered trademark), Code Division Multiple Access (CDMA), Wideband-Code Division Multiple Access (W-CDMA), Long Term Evolution (LTE), and High Speed Packet Access (HSPA). Alternatively, the cellular phone ex 114  may be a Personal Handyphone System (PHS). 
     In the content providing system ex 100 , a streaming server ex 103  is connected to the camera ex 113  and others via the telephone network ex 104  and the base station ex 109 , which enables distribution of images of a live show and others. In such a distribution, a content (for example, video of a music live show) captured by the user using the camera ex 113  is coded as described above in each of embodiments (i.e., the camera functions as the image coding apparatus according to an aspect of the present disclosure), and the coded content is transmitted to the streaming server ex 103 . On the other hand, the streaming server ex 103  carries out stream distribution of the transmitted content data to the clients upon their requests. The clients include the computer ex 111 , the PDA ex 112 , the camera ex 113 , the cellular phone ex 114 , and the game machine ex 115  that are capable of decoding the above-mentioned coded data. Each of the devices that have received the distributed data decodes and reproduces the coded data (i.e., functions as the image decoding apparatus according to an aspect of the present disclosure). 
     The captured data may be coded by the camera ex 113  or the streaming server ex 103  that transmits the data, or the coding processes may be shared between the camera ex 113  and the streaming server ex 103 . Similarly, the distributed data may be decoded by the clients or the streaming server ex 103 , or the decoding processes may be shared between the clients and the streaming server ex 103 . Furthermore, the data of the still images and video captured by not only the camera ex 113  but also the camera ex 116  may be transmitted to the streaming server ex 103  through the computer ex 111 . The coding processes may be performed by the camera ex 116 , the computer ex 111 , or the streaming server ex 103 , or shared among them. 
     Furthermore, the coding and decoding processes may be performed by an LSI ex 500  generally included in each of the computer ex 111  and the devices. The LSI ex 500  may be configured of a single chip or a plurality of chips. Software for coding and decoding video may be integrated into some type of a recording medium (such as a CD-ROM, a flexible disk, and a hard disk) that is readable by the computer ex 111  and others, and the coding and decoding processes may be performed using the software. Furthermore, when the cellular phone ex 114  is equipped with a camera, the video data obtained by the camera may be transmitted. The video data is data coded by the LSI ex 500  included in the cellular phone ex 114 . 
     Furthermore, the streaming server ex 103  may be composed of servers and computers, and may decentralize data and process the decentralized data, record, or distribute data. 
     As described above, the clients may receive and reproduce the coded data in the content providing system ex 100 . In other words, the clients can receive and decode information transmitted by the user, and reproduce the decoded data in real time in the content providing system ex 100 , so that the user who does not have any particular right and equipment can implement personal broadcasting. 
     Aside from the example of the content providing system ex 100 , at least one of the moving picture coding apparatus (image coding apparatus) and the moving picture decoding apparatus (image decoding apparatus) described in each of embodiments may be implemented in a digital broadcasting system ex 200  illustrated in  FIG.  25   . More specifically, a broadcast station ex 201  communicates or transmits, via radio waves to a broadcast satellite ex 202 , multiplexed data obtained by multiplexing audio data and others onto video data. The video data is data coded by the moving picture coding method described in each of embodiments (i.e., data coded by the image coding apparatus according to an aspect of the present disclosure). Upon receipt of the multiplexed data, the broadcast satellite ex 202  transmits radio waves for broadcasting. Then, a home-use antenna ex 204  with a satellite broadcast reception function receives the radio waves. Next, a device such as a television (receiver) ex 300  and a set top box (STB) ex 217  decodes the received multiplexed data, and reproduces the decoded data (i.e., functions as the image decoding apparatus according to an aspect of the present disclosure). 
     Furthermore, a reader/recorder ex 218  (i) reads and decodes the multiplexed data recorded on a recording medium ex 215 , such as a DVD and a BD, or (i) codes video signals in the recording medium ex 215 , and in some cases, writes data obtained by multiplexing an audio signal on the coded data. The reader/recorder ex 218  can include the moving picture decoding apparatus or the moving picture coding apparatus as shown in each of embodiments. In this case, the reproduced video signals are displayed on the monitor ex 219 , and can be reproduced by another device or system using the recording medium ex 215  on which the multiplexed data is recorded. It is also possible to implement the moving picture decoding apparatus in the set top box ex 217  connected to the cable ex 203  for a cable television or to the antenna ex 204  for satellite and/or terrestrial broadcasting, so as to display the video signals on the monitor ex 219  of the television ex 300 . The moving picture decoding apparatus may be implemented not in the set top box but in the television ex 300 . 
       FIG.  26    illustrates the television (receiver) ex 300  that uses the moving picture coding method and the moving picture decoding method described in each of embodiments. The television ex 300  includes: a tuner ex 301  that obtains or provides multiplexed data obtained by multiplexing audio data onto video data, through the antenna ex 204  or the cable ex 203 , etc. that receives a broadcast; a modulation/demodulation unit ex 302  that demodulates the received multiplexed data or modulates data into multiplexed data to be supplied outside; and a multiplexing/demultiplexing unit ex 303  that demultiplexes the modulated multiplexed data into video data and audio data, or multiplexes video data and audio data coded by a signal processing unit ex 306  into data. 
     The television ex 300  further includes: a signal processing unit ex 306  including an audio signal processing unit ex 304  and a video signal processing unit ex 305  that decode audio data and video data and code audio data and video data, respectively (which function as the image coding apparatus and the image decoding apparatus according to the aspects of the present disclosure); and an output unit ex 309  including a speaker ex 307  that provides the decoded audio signal, and a display unit ex 308  that displays the decoded video signal, such as a display. Furthermore, the television ex 300  includes an interface unit ex 317  including an operation input unit ex 312  that receives an input of a user operation. Furthermore, the television ex 300  includes a control unit ex 310  that controls overall each constituent element of the television ex 300 , and a power supply circuit unit ex 311  that supplies power to each of the elements. Other than the operation input unit ex 312 , the interface unit ex 317  may include: a bridge ex 313  that is connected to an external device, such as the reader/recorder ex 218 ; a slot unit ex 314  for enabling attachment of the recording medium ex 216 , such as an SD card; a driver ex 315  to be connected to an external recording medium, such as a hard disk; and a modem ex 316  to be connected to a telephone network. Here, the recording medium ex 216  can electrically record information using a non-volatile/volatile semiconductor memory element for storage. The constituent elements of the television ex 300  are connected to each other through a synchronous bus. 
     First, the configuration in which the television ex 300  decodes multiplexed data obtained from outside through the antenna ex 204  and others and reproduces the decoded data will be described. In the television ex 300 , upon a user operation through a remote controller ex 220  and others, the multiplexing/demultiplexing unit ex 303  demultiplexes the multiplexed data demodulated by the modulation/demodulation unit ex 302 , under control of the control unit ex 310  including a CPU. Furthermore, the audio signal processing unit ex 304  decodes the demultiplexed audio data, and the video signal processing unit ex 305  decodes the demultiplexed video data, using the decoding method described in each of embodiments, in the television ex 300 . The output unit ex 309  provides the decoded video signal and audio signal outside, respectively. When the output unit ex 309  provides the video signal and the audio signal, the signals may be temporarily stored in buffers ex 318  and ex 319 , and others so that the signals are reproduced in synchronization with each other. Furthermore, the television ex 300  may read multiplexed data not through a broadcast and others but from the recording media ex 215  and ex 216 , such as a magnetic disk, an optical disk, and a SD card. Next, a configuration in which the television ex 300  codes an audio signal and a video signal, and transmits the data outside or writes the data on a recording medium will be described. In the television ex 300 , upon a user operation through the remote controller ex 220  and others, the audio signal processing unit ex 304  codes an audio signal, and the video signal processing unit ex 305  codes a video signal, under control of the control unit ex 310  using the coding method described in each of embodiments. The multiplexing/demultiplexing unit ex 303  multiplexes the coded video signal and audio signal, and provides the resulting signal outside. When the multiplexing/demultiplexing unit ex 303  multiplexes the video signal and the audio signal, the signals may be temporarily stored in the buffers ex 320  and ex 321 , and others so that the signals are reproduced in synchronization with each other. Here, the buffers ex 318 , ex 319 , ex 320 , and ex 321  may be plural as illustrated, or at least one buffer may be shared in the television ex 300 . Furthermore, data may be stored in a buffer so that the system overflow and underflow may be avoided between the modulation/demodulation unit ex 302  and the multiplexing/demultiplexing unit ex 303 , for example. 
     Furthermore, the television ex 300  may include a configuration for receiving an AV input from a microphone or a camera other than the configuration for obtaining audio and video data from a broadcast or a recording medium, and may code the obtained data. Although the television ex 300  can code, multiplex, and provide outside data in the description, it may be capable of only receiving, decoding, and providing outside data but not the coding, multiplexing, and providing outside data. 
     Furthermore, when the reader/recorder ex 218  reads or writes multiplexed data from or on a recording medium, one of the television ex 300  and the reader/recorder ex 218  may decode or code the multiplexed data, and the television ex 300  and the reader/recorder ex 218  may share the decoding or coding. 
     As an example,  FIG.  27    illustrates a configuration of an information reproducing/recording unit ex 400  when data is read or written from or on an optical disk. The information reproducing/recording unit ex 400  includes constituent elements ex 401 , ex 402 , ex 403 , ex 404 , ex 405 , ex 406 , and ex 407  to be described hereinafter. The optical head ex 401  irradiates a laser spot in a recording surface of the recording medium ex 215  that is an optical disk to write information, and detects reflected light from the recording surface of the recording medium ex 215  to read the information. The modulation recording unit ex 402  electrically drives a semiconductor laser included in the optical head ex 401 , and modulates the laser light according to recorded data. The reproduction demodulating unit ex 403  amplifies a reproduction signal obtained by electrically detecting the reflected light from the recording surface using a photo detector included in the optical head ex 401 , and demodulates the reproduction signal by separating a signal component recorded on the recording medium ex 215  to reproduce the necessary information. The buffer ex 404  temporarily holds the information to be recorded on the recording medium ex 215  and the information reproduced from the recording medium ex 215 . The disk motor ex 405  rotates the recording medium ex 215 . The servo control unit ex 406  moves the optical head ex 401  to a predetermined information track while controlling the rotation drive of the disk motor ex 405  so as to follow the laser spot. The system control unit ex 407  controls overall the information reproducing/recording unit ex 400 . The reading and writing processes can be implemented by the system control unit ex 407  using various information stored in the buffer ex 404  and generating and adding new information as necessary, and by the modulation recording unit ex 402 , the reproduction demodulating unit ex 403 , and the servo control unit ex 406  that record and reproduce information through the optical head ex 401  while being operated in a coordinated manner. The system control unit ex 407  includes, for example, a microprocessor, and executes processing by causing a computer to execute a program for read and write. 
     Although the optical head ex 401  irradiates a laser spot in the description, it may perform high-density recording using near field light. 
       FIG.  28    illustrates the recording medium ex 215  that is the optical disk. On the recording surface of the recording medium ex 215 , guide grooves are spirally formed, and an information track ex 230  records, in advance, address information indicating an absolute position on the disk according to change in a shape of the guide grooves. The address information includes information for determining positions of recording blocks ex 231  that are a unit for recording data. Reproducing the information track ex 230  and reading the address information in an apparatus that records and reproduces data can lead to determination of the positions of the recording blocks. Furthermore, the recording medium ex 215  includes a data recording area ex 233 , an inner circumference area ex 232 , and an outer circumference area ex 234 . The data recording area ex 233  is an area for use in recording the user data. The inner circumference area ex 232  and the outer circumference area ex 234  that are inside and outside of the data recording area ex 233 , respectively are for specific use except for recording the user data. The information reproducing/recording unit  400  reads and writes coded audio, coded video data, or multiplexed data obtained by multiplexing the coded audio and video data, from and on the data recording area ex 233  of the recording medium ex 215 . 
     Although an optical disk having a layer, such as a DVD and a BD is described as an example in the description, the optical disk is not limited to such, and may be an optical disk having a multilayer structure and capable of being recorded on a part other than the surface. Furthermore, the optical disk may have a structure for multidimensional recording/reproduction, such as recording of information using light of colors with different wavelengths in the same portion of the optical disk and for recording information having different layers from various angles. 
     Furthermore, a car ex 210  having an antenna ex 205  can receive data from the satellite ex 202  and others, and reproduce video on a display device such as a car navigation system ex 211  set in the car ex 210 , in the digital broadcasting system ex 200 . Here, a configuration of the car navigation system ex 211  will be a configuration, for example, including a GPS receiving unit from the configuration illustrated in  FIG.  26   . The same will be true for the configuration of the computer ex 111 , the cellular phone ex 114 , and others. 
       FIG.  29 A  illustrates the cellular phone ex 114  that uses the moving picture coding method and the moving picture decoding method described in embodiments. The cellular phone ex 114  includes: an antenna ex 350  for transmitting and receiving radio waves through the base station ex 110 ; a camera unit ex 365  capable of capturing moving and still images; and a display unit ex 358  such as a liquid crystal display for displaying the data such as decoded video captured by the camera unit ex 365  or received by the antenna ex 350 . The cellular phone ex 114  further includes: a main body unit including an operation key unit ex 366 ; an audio output unit ex 357  such as a speaker for output of audio; an audio input unit ex 356  such as a microphone for input of audio; a memory unit ex 367  for storing captured video or still pictures, recorded audio, coded or decoded data of the received video, the still pictures, e-mails, or others; and a slot unit ex 364  that is an interface unit for a recording medium that stores data in the same manner as the memory unit ex 367 . 
     Next, an example of a configuration of the cellular phone ex 114  will be described with reference to  FIG.  29 B . In the cellular phone ex 114 , a main control unit ex 360  designed to control overall each unit of the main body including the display unit ex 358  as well as the operation key unit ex 366  is connected mutually, via a synchronous bus ex 370 , to a power supply circuit unit ex 361 , an operation input control unit ex 362 , a video signal processing unit ex 355 , a camera interface unit ex 363 , a liquid crystal display (LCD) control unit ex 359 , a modulation/demodulation unit ex 352 , a multiplexing/demultiplexing unit ex 353 , an audio signal processing unit ex 354 , the slot unit ex 364 , and the memory unit ex 367 . 
     When a call-end key or a power key is turned ON by a user&#39;s operation, the power supply circuit unit ex 361  supplies the respective units with power from a battery pack so as to activate the cell phone ex 114 . 
     In the cellular phone ex 114 , the audio signal processing unit ex 354  converts the audio signals collected by the audio input unit ex 356  in voice conversation mode into digital audio signals under the control of the main control unit ex 360  including a CPU, ROM, and RAM. Then, the modulation/demodulation unit ex 352  performs spread spectrum processing on the digital audio signals, and the transmitting and receiving unit ex 351  performs digital-to-analog conversion and frequency conversion on the data, so as to transmit the resulting data via the antenna ex 350 . Also, in the cellular phone ex 114 , the transmitting and receiving unit ex 351  amplifies the data received by the antenna ex 350  in voice conversation mode and performs frequency conversion and the analog-to-digital conversion on the data. Then, the modulation/demodulation unit ex 352  performs inverse spread spectrum processing on the data, and the audio signal processing unit ex 354  converts it into analog audio signals, so as to output them via the audio output unit ex 357 . 
     Furthermore, when an e-mail in data communication mode is transmitted, text data of the e-mail inputted by operating the operation key unit ex 366  and others of the main body is sent out to the main control unit ex 360  via the operation input control unit ex 362 . The main control unit ex 360  causes the modulation/demodulation unit ex 352  to perform spread spectrum processing on the text data, and the transmitting and receiving unit ex 351  performs the digital-to-analog conversion and the frequency conversion on the resulting data to transmit the data to the base station ex 110  via the antenna ex 350 . When an e-mail is received, processing that is approximately inverse to the processing for transmitting an e-mail is performed on the received data, and the resulting data is provided to the display unit ex 358 . 
     When video, still images, or video and audio in data communication mode is or are transmitted, the video signal processing unit ex 355  compresses and codes video signals supplied from the camera unit ex 365  using the moving picture coding method shown in each of embodiments (i.e., functions as the image coding apparatus according to the aspect of the present disclosure), and transmits the coded video data to the multiplexing/demultiplexing unit ex 353 . In contrast, during when the camera unit ex 365  captures video, still images, and others, the audio signal processing unit ex 354  codes audio signals collected by the audio input unit ex 356 , and transmits the coded audio data to the multiplexing/demultiplexing unit ex 353 . 
     The multiplexing/demultiplexing unit ex 353  multiplexes the coded video data supplied from the video signal processing unit ex 355  and the coded audio data supplied from the audio signal processing unit ex 354 , using a predetermined method. Then, the modulation/demodulation unit (modulation/demodulation circuit unit) ex 352  performs spread spectrum processing on the multiplexed data, and the transmitting and receiving unit ex 351  performs digital-to-analog conversion and frequency conversion on the data so as to transmit the resulting data via the antenna ex 350 . 
     When receiving data of a video file which is linked to a Web page and others in data communication mode or when receiving an e-mail with video and/or audio attached, in order to decode the multiplexed data received via the antenna ex 350 , the multiplexing/demultiplexing unit ex 353  demultiplexes the multiplexed data into a video data bit stream and an audio data bit stream, and supplies the video signal processing unit ex 355  with the coded video data and the audio signal processing unit ex 354  with the coded audio data, through the synchronous bus ex 370 . The video signal processing unit ex 355  decodes the video signal using a moving picture decoding method corresponding to the moving picture coding method shown in each of embodiments (i.e., functions as the image decoding apparatus according to the aspect of the present disclosure), and then the display unit ex 358  displays, for instance, the video and still images included in the video file linked to the Web page via the LCD control unit ex 359 . Furthermore, the audio signal processing unit ex 354  decodes the audio signal, and the audio output unit ex 357  provides the audio. 
     Furthermore, similarly to the television ex 300 , a terminal such as the cellular phone ex 114  probably have 3 types of implementation configurations including not only (i) a transmitting and receiving terminal including both a coding apparatus and a decoding apparatus, but also (ii) a transmitting terminal including only a coding apparatus and (iii) a receiving terminal including only a decoding apparatus. Although the digital broadcasting system ex 200  receives and transmits the multiplexed data obtained by multiplexing audio data onto video data in the description, the multiplexed data may be data obtained by multiplexing not audio data but character data related to video onto video data, and may be not multiplexed data but video data itself. 
     As such, the moving picture coding method and the moving picture decoding method in each of embodiments can be used in any of the devices and systems described. Thus, the advantages described in each of embodiments can be obtained. 
     Furthermore, the present disclosure is not limited to the above embodiments, and various modifications and revisions are possible without departing from the scope of the present disclosure. 
     Embodiment 5 
     Video data can be generated by switching, as necessary, between (i) the moving picture coding method or the moving picture coding apparatus shown in each of embodiments and (ii) a moving picture coding method or a moving picture coding apparatus in conformity with a different standard, such as MPEG-2, MPEG-4 AVC, and VC-1. 
     Here, when a plurality of video data that conforms to the different standards is generated and is then decoded, the decoding methods need to be selected to conform to the different standards. However, since to which standard each of the plurality of the video data to be decoded conform cannot be detected, there is a problem that an appropriate decoding method cannot be selected. 
     In order to solve the problem, multiplexed data obtained by multiplexing audio data and others onto video data has a structure including identification information indicating to which standard the video data conforms. The specific structure of the multiplexed data including the video data generated in the moving picture coding method and by the moving picture coding apparatus shown in each of embodiments will be hereinafter described. The multiplexed data is a digital stream in the MPEG-2 Transport Stream format. 
       FIG.  30    illustrates a structure of the multiplexed data. As illustrated in  FIG.  30   , the multiplexed data can be obtained by multiplexing at least one of a video stream, an audio stream, a presentation graphics stream (PG), and an interactive graphics stream. The video stream represents primary video and secondary video of a movie, the audio stream (IG) represents a primary audio part and a secondary audio part to be mixed with the primary audio part, and the presentation graphics stream represents subtitles of the movie. Here, the primary video is normal video to be displayed on a screen, and the secondary video is video to be displayed on a smaller window in the primary video. Furthermore, the interactive graphics stream represents an interactive screen to be generated by arranging the GUI components on a screen. The video stream is coded in the moving picture coding method or by the moving picture coding apparatus shown in each of embodiments, or in a moving picture coding method or by a moving picture coding apparatus in conformity with a conventional standard, such as MPEG-2, MPEG-4 AVC, and VC-1. The audio stream is coded in accordance with a standard, such as Dolby-AC-3, Dolby Digital Plus, MLP, DTS, DTS-HD, and linear PCM. 
     Each stream included in the multiplexed data is identified by PID. For example, 0x1011 is allocated to the video stream to be used for video of a movie, 0x1100 to 0x111F are allocated to the audio streams, 0x1200 to 0x121F are allocated to the presentation graphics streams, 0x1400 to 0x141F are allocated to the interactive graphics streams, 0x1B00 to 0x1B1F are allocated to the video streams to be used for secondary video of the movie, and 0x1A00 to 0x1A1F are allocated to the audio streams to be used for the secondary audio to be mixed with the primary audio. 
       FIG.  31    schematically illustrates how data is multiplexed. First, a video stream ex 235  composed of video frames and an audio stream ex 238  composed of audio frames are transformed into a stream of PES packets ex 236  and a stream of PES packets ex 239 , and further into TS packets ex 237  and TS packets ex 240 , respectively. Similarly, data of a presentation graphics stream ex 241  and data of an interactive graphics stream ex 244  are transformed into a stream of PES packets ex 242  and a stream of PES packets ex 245 , and further into TS packets ex 243  and TS packets ex 246 , respectively. These TS packets are multiplexed into a stream to obtain multiplexed data ex 247 . 
       FIG.  32    illustrates how a video stream is stored in a stream of PES packets in more detail. The first bar in  FIG.  32    shows a video frame stream in a video stream. The second bar shows the stream of PES packets. As indicated by arrows denoted as yy 1 , yy 2 , yy 3 , and yy 4  in  FIG.  32   , the video stream is divided into pictures as I pictures, B pictures, and P pictures each of which is a video presentation unit, and the pictures are stored in a payload of each of the PES packets. Each of the PES packets has a PES header, and the PES header stores a Presentation Time-Stamp (PTS) indicating a display time of the picture, and a Decoding Time-Stamp (DTS) indicating a decoding time of the picture. 
       FIG.  33    illustrates a format of TS packets to be finally written on the multiplexed data. Each of the TS packets is a 188-byte fixed length packet including a 4-byte TS header having information, such as a PID for identifying a stream and a 184-byte TS payload for storing data. The PES packets are divided, and stored in the TS payloads, respectively. When a BD ROM is used, each of the TS packets is given a 4-byte TP_Extra_Header, thus resulting in 192-byte source packets. The source packets are written on the multiplexed data. The TP_Extra_Header stores information such as an Arrival_Time_Stamp (ATS). The ATS shows a transfer start time at which each of the TS packets is to be transferred to a PID filter. The source packets are arranged in the multiplexed data as shown at the bottom of  FIG.  33   . The numbers incrementing from the head of the multiplexed data are called source packet numbers (SPNs). 
     Each of the TS packets included in the multiplexed data includes not only streams of audio, video, subtitles and others, but also a Program Association Table (PAT), a Program Map Table (PMT), and a Program Clock Reference (PCR). The PAT shows what a PID in a PMT used in the multiplexed data indicates, and a PID of the PAT itself is registered as zero. The PMT stores PIDs of the streams of video, audio, subtitles and others included in the multiplexed data, and attribute information of the streams corresponding to the PIDs. The PMT also has various descriptors relating to the multiplexed data. The descriptors have information such as copy control information showing whether copying of the multiplexed data is permitted or not. The PCR stores STC time information corresponding to an ATS showing when the PCR packet is transferred to a decoder, in order to achieve synchronization between an Arrival Time Clock (ATC) that is a time axis of ATSs, and an System Time Clock (STC) that is a time axis of PTSs and DTSs. 
       FIG.  34    illustrates the data structure of the PMT in detail. A PMT header is disposed at the top of the PMT. The PMT header describes the length of data included in the PMT and others. A plurality of descriptors relating to the multiplexed data is disposed after the PMT header. Information such as the copy control information is described in the descriptors. After the descriptors, a plurality of pieces of stream information relating to the streams included in the multiplexed data is disposed. Each piece of stream information includes stream descriptors each describing information, such as a stream type for identifying a compression codec of a stream, a stream PID, and stream attribute information (such as a frame rate or an aspect ratio). The stream descriptors are equal in number to the number of streams in the multiplexed data. 
     When the multiplexed data is recorded on a recording medium and others, it is recorded together with multiplexed data information files. 
     Each of the multiplexed data information files is management information of the multiplexed data as shown in  FIG.  35   . The multiplexed data information files are in one to one correspondence with the multiplexed data, and each of the files includes multiplexed data information, stream attribute information, and an entry map. 
     As illustrated in  FIG.  35   , the multiplexed data information includes a system rate, a reproduction start time, and a reproduction end time. The system rate indicates the maximum transfer rate at which a system target decoder to be described later transfers the multiplexed data to a PID filter. The intervals of the ATSs included in the multiplexed data are set to not higher than a system rate. The reproduction start time indicates a PTS in a video frame at the head of the multiplexed data. An interval of one frame is added to a PTS in a video frame at the end of the multiplexed data, and the PTS is set to the reproduction end time. 
     As shown in  FIG.  36   , a piece of attribute information is registered in the stream attribute information, for each PID of each stream included in the multiplexed data. Each piece of attribute information has different information depending on whether the corresponding stream is a video stream, an audio stream, a presentation graphics stream, or an interactive graphics stream. Each piece of video stream attribute information carries information including what kind of compression codec is used for compressing the video stream, and the resolution, aspect ratio and frame rate of the pieces of picture data that is included in the video stream. Each piece of audio stream attribute information carries information including what kind of compression codec is used for compressing the audio stream, how many channels are included in the audio stream, which language the audio stream supports, and how high the sampling frequency is. The video stream attribute information and the audio stream attribute information are used for initialization of a decoder before the player plays back the information. 
     In the present embodiment, the multiplexed data to be used is of a stream type included in the PMT. Furthermore, when the multiplexed data is recorded on a recording medium, the video stream attribute information included in the multiplexed data information is used. More specifically, the moving picture coding method or the moving picture coding apparatus described in each of embodiments includes a step or a unit for allocating unique information indicating video data generated by the moving picture coding method or the moving picture coding apparatus in each of embodiments, to the stream type included in the PMT or the video stream attribute information. With the configuration, the video data generated by the moving picture coding method or the moving picture coding apparatus described in each of embodiments can be distinguished from video data that conforms to another standard. 
     Furthermore,  FIG.  37    illustrates steps of the moving picture decoding method according to the present embodiment. In Step exS 100 , the stream type included in the PMT or the video stream attribute information included in the multiplexed data information is obtained from the multiplexed data. Next, in Step exS 101 , it is determined whether or not the stream type or the video stream attribute information indicates that the multiplexed data is generated by the moving picture coding method or the moving picture coding apparatus in each of embodiments. When it is determined that the stream type or the video stream attribute information indicates that the multiplexed data is generated by the moving picture coding method or the moving picture coding apparatus in each of embodiments, in Step exS 102 , decoding is performed by the moving picture decoding method in each of embodiments. Furthermore, when the stream type or the video stream attribute information indicates conformance to the conventional standards, such as MPEG-2, MPEG-4 AVC, and VC-1, in Step exS 103 , decoding is performed by a moving picture decoding method in conformity with the conventional standards. 
     As such, allocating a new unique value to the stream type or the video stream attribute information enables determination whether or not the moving picture decoding method or the moving picture decoding apparatus that is described in each of embodiments can perform decoding. Even when multiplexed data that conforms to a different standard is input, an appropriate decoding method or apparatus can be selected. Thus, it becomes possible to decode information without any error. Furthermore, the moving picture coding method or apparatus, or the moving picture decoding method or apparatus in the present embodiment can be used in the devices and systems described above. 
     Embodiment 6 
     Each of the moving picture coding method, the moving picture coding apparatus, the moving picture decoding method, and the moving picture decoding apparatus in each of embodiments is typically achieved in the form of an integrated circuit or a Large Scale Integrated (LSI) circuit. As an example of the LSI,  FIG.  38    illustrates a configuration of the LSI ex 500  that is made into one chip. The LSI ex 500  includes elements ex 501 , ex 502 , ex 503 , ex 504 , ex 505 , ex 506 , ex 507 , ex 508 , and ex 509  to be described below, and the elements are connected to each other through a bus ex 510 . The power supply circuit unit ex 505  is activated by supplying each of the elements with power when the power supply circuit unit ex 505  is turned on. 
     For example, when coding is performed, the LSI ex 500  receives an AV signal from a microphone ex 117 , a camera ex 113 , and others through an AV IO ex 509  under control of a control unit ex 501  including a CPU ex 502 , a memory controller ex 503 , a stream controller ex 504 , and a driving frequency control unit ex 512 . The received AV signal is temporarily stored in an external memory ex 511 , such as an SDRAM. Under control of the control unit ex 501 , the stored data is segmented into data portions according to the processing amount and speed to be transmitted to a signal processing unit ex 507 . Then, the signal processing unit ex 507  codes an audio signal and/or a video signal. Here, the coding of the video signal is the coding described in each of embodiments. Furthermore, the signal processing unit ex 507  sometimes multiplexes the coded audio data and the coded video data, and a stream IO ex 506  provides the multiplexed data outside. The provided multiplexed data is transmitted to the base station ex 107 , or written on the recording medium ex 215 . When data sets are multiplexed, the data should be temporarily stored in the buffer ex 508  so that the data sets are synchronized with each other. 
     Although the memory ex 511  is an element outside the LSI ex 500 , it may be included in the LSI ex 500 . The buffer ex 508  is not limited to one buffer, but may be composed of buffers. Furthermore, the LSI ex 500  may be made into one chip or a plurality of chips. 
     Furthermore, although the control unit ex 501  includes the CPU ex 502 , the memory controller ex 503 , the stream controller ex 504 , the driving frequency control unit ex 512 , the configuration of the control unit ex 501  is not limited to such. For example, the signal processing unit ex 507  may further include a CPU. Inclusion of another CPU in the signal processing unit ex 507  can improve the processing speed. Furthermore, as another example, the CPU ex 502  may serve as or be a part of the signal processing unit ex 507 , and, for example, may include an audio signal processing unit. In such a case, the control unit ex 501  includes the signal processing unit ex 507  or the CPU ex 502  including a part of the signal processing unit ex 507 . 
     The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration. 
     Moreover, ways to achieve integration are not limited to the LSI, and a special circuit or a general purpose processor and so forth can also achieve the integration. Field Programmable Gate Array (FPGA) that can be programmed after manufacturing LSIs or a reconfigurable processor that allows re-configuration of the connection or configuration of an LSI can be used for the same purpose. 
     In the future, with advancement in semiconductor technology, a brand-new technology may replace LSI. The functional blocks can be integrated using such a technology. The possibility is that the present disclosure is applied to biotechnology. 
     Embodiment 7 
     When video data generated in the moving picture coding method or by the moving picture coding apparatus described in each of embodiments is decoded, compared to when video data that conforms to a conventional standard, such as MPEG-2, MPEG-4 AVC, and VC-1 is decoded, the processing amount probably increases. Thus, the LSI ex 500  needs to be set to a driving frequency higher than that of the CPU ex 502  to be used when video data in conformity with the conventional standard is decoded. However, when the driving frequency is set higher, there is a problem that the power consumption increases. 
     In order to solve the problem, the moving picture decoding apparatus, such as the television ex 300  and the LSI ex 500  is configured to determine to which standard the video data conforms, and switch between the driving frequencies according to the determined standard.  FIG.  39    illustrates a configuration ex 800  in the present embodiment. A driving frequency switching unit ex 803  sets a driving frequency to a higher driving frequency when video data is generated by the moving picture coding method or the moving picture coding apparatus described in each of embodiments. Then, the driving frequency switching unit ex 803  instructs a decoding processing unit ex 801  that executes the moving picture decoding method described in each of embodiments to decode the video data. When the video data conforms to the conventional standard, the driving frequency switching unit ex 803  sets a driving frequency to a lower driving frequency than that of the video data generated by the moving picture coding method or the moving picture coding apparatus described in each of embodiments. Then, the driving frequency switching unit ex 803  instructs the decoding processing unit ex 802  that conforms to the conventional standard to decode the video data. 
     More specifically, the driving frequency switching unit ex 803  includes the CPU ex 502  and the driving frequency control unit ex 512  in  FIG.  38   . Here, each of the decoding processing unit ex 801  that executes the moving picture decoding method described in each of embodiments and the decoding processing unit ex 802  that conforms to the conventional standard corresponds to the signal processing unit ex 507  in  FIG.  38   . The CPU ex 502  determines to which standard the video data conforms. Then, the driving frequency control unit ex 512  determines a driving frequency based on a signal from the CPU ex 502 . Furthermore, the signal processing unit ex 507  decodes the video data based on the signal from the CPU ex 502 . For example, the identification information described in Embodiment 5 is probably used for identifying the video data. The identification information is not limited to the one described in Embodiment 5 but may be any information as long as the information indicates to which standard the video data conforms. For example, when which standard video data conforms to can be determined based on an external signal for determining that the video data is used for a television or a disk, etc., the determination may be made based on such an external signal. Furthermore, the CPU ex 502  selects a driving frequency based on, for example, a look-up table in which the standards of the video data are associated with the driving frequencies as shown in  FIG.  127   . The driving frequency can be selected by storing the look-up table in the buffer ex 508  and in an internal memory of an LSI, and with reference to the look-up table by the CPU ex 502 . 
       FIG.  40    illustrates steps for executing a method in the present embodiment. First, in Step exS 200 , the signal processing unit ex 507  obtains identification information from the multiplexed data. Next, in Step exS 201 , the CPU ex 502  determines whether or not the video data is generated by the coding method and the coding apparatus described in each of embodiments, based on the identification information. When the video data is generated by the moving picture coding method and the moving picture coding apparatus described in each of embodiments, in Step exS 202 , the CPU ex 502  transmits a signal for setting the driving frequency to a higher driving frequency to the driving frequency control unit ex 512 . Then, the driving frequency control unit ex 512  sets the driving frequency to the higher driving frequency. On the other hand, when the identification information indicates that the video data conforms to the conventional standard, such as MPEG-2, MPEG-4 AVC, and VC-1, in Step exS 203 , the CPU ex 502  transmits a signal for setting the driving frequency to a lower driving frequency to the driving frequency control unit ex 512 . Then, the driving frequency control unit ex 512  sets the driving frequency to the lower driving frequency than that in the case where the video data is generated by the moving picture coding method and the moving picture coding apparatus described in each of embodiment. 
     Furthermore, along with the switching of the driving frequencies, the power conservation effect can be improved by changing the voltage to be applied to the LSI ex 500  or an apparatus including the LSI ex 500 . For example, when the driving frequency is set lower, the voltage to be applied to the LSI ex 500  or the apparatus including the LSI ex 500  is probably set to a voltage lower than that in the case where the driving frequency is set higher. 
     Furthermore, when the processing amount for decoding is larger, the driving frequency may be set higher, and when the processing amount for decoding is smaller, the driving frequency may be set lower as the method for setting the driving frequency. Thus, the setting method is not limited to the ones described above. For example, when the processing amount for decoding video data in conformity with MPEG-4 AVC is larger than the processing amount for decoding video data generated by the moving picture coding method and the moving picture coding apparatus described in each of embodiments, the driving frequency is probably set in reverse order to the setting described above. 
     Furthermore, the method for setting the driving frequency is not limited to the method for setting the driving frequency lower. For example, when the identification information indicates that the video data is generated by the moving picture coding method and the moving picture coding apparatus described in each of embodiments, the voltage to be applied to the LSI ex 500  or the apparatus including the LSI ex 500  is probably set higher. When the identification information indicates that the video data conforms to the conventional standard, such as MPEG-2, MPEG-4 AVC, and VC-1, the voltage to be applied to the LSI ex 500  or the apparatus including the LSI ex 500  is probably set lower. As another example, when the identification information indicates that the video data is generated by the moving picture coding method and the moving picture coding apparatus described in each of embodiments, the driving of the CPU ex 502  does not probably have to be suspended. When the identification information indicates that the video data conforms to the conventional standard, such as MPEG-2, MPEG-4 AVC, and VC-1, the driving of the CPU ex 502  is probably suspended at a given time because the CPU ex 502  has extra processing capacity. Even when the identification information indicates that the video data is generated by the moving picture coding method and the moving picture coding apparatus described in each of embodiments, in the case where the CPU ex 502  has extra processing capacity, the driving of the CPU ex 502  is probably suspended at a given time. In such a case, the suspending time is probably set shorter than that in the case where when the identification information indicates that the video data conforms to the conventional standard, such as MPEG-2, MPEG-4 AVC, and VC-1. 
     Accordingly, the power conservation effect can be improved by switching between the driving frequencies in accordance with the standard to which the video data conforms. Furthermore, when the LSI ex 500  or the apparatus including the LSI ex 500  is driven using a battery, the battery life can be extended with the power conservation effect. 
     Embodiment 8 
     There are cases where a plurality of video data that conforms to different standards, is provided to the devices and systems, such as a television and a cellular phone. In order to enable decoding the plurality of video data that conforms to the different standards, the signal processing unit ex 507  of the LSI ex 500  needs to conform to the different standards. However, the problems of increase in the scale of the circuit of the LSI ex 500  and increase in the cost arise with the individual use of the signal processing units ex 507  that conform to the respective standards. 
     In order to solve the problem, what is conceived is a configuration in which the decoding processing unit for implementing the moving picture decoding method described in each of embodiments and the decoding processing unit that conforms to the conventional standard, such as MPEG-2, MPEG-4 AVC, and VC-1 are partly shared. Ex 900  in  FIG.  42 A  shows an example of the configuration. For example, the moving picture decoding method described in each of embodiments and the moving picture decoding method that conforms to MPEG-4 AVC have, partly in common, the details of processing, such as entropy coding, inverse quantization, deblocking filtering, and motion compensated prediction. The details of processing to be shared probably include use of a decoding processing unit ex 902  that conforms to MPEG-4 AVC. In contrast, a dedicated decoding processing unit ex 901  is probably used for other processing unique to an aspect of the present disclosure. The decoding processing unit for implementing the moving picture decoding method described in each of embodiments may be shared for the processing to be shared, and a dedicated decoding processing unit may be used for processing unique to that of MPEG-4 AVC. 
     Furthermore, ex 1000  in  FIG.  42 B  shows another example in that processing is partly shared. This example uses a configuration including a dedicated decoding processing unit ex 1001  that supports the processing unique to an aspect of the present disclosure, a dedicated decoding processing unit ex 1002  that supports the processing unique to another conventional standard, and a decoding processing unit ex 1003  that supports processing to be shared between the moving picture decoding method according to the aspect of the present disclosure and the conventional moving picture decoding method. Here, the dedicated decoding processing units ex 1001  and ex 1002  are not necessarily specialized for the processing according to the aspect of the present disclosure and the processing of the conventional standard, respectively, and may be the ones capable of implementing general processing. Furthermore, the configuration of the present embodiment can be implemented by the LSI ex 500 . 
     As such, reducing the scale of the circuit of an LSI and reducing the cost are possible by sharing the decoding processing unit for the processing to be shared between the moving picture decoding method according to the aspect of the present disclosure and the moving picture decoding method in conformity with the conventional standard. 
     Although the above is a description of exemplary embodiments, the scope of the claims of the present application is not limited to those embodiments. Without departing from novel teaching and advantages of a subject matter described in the appended claims, various modifications may be made to the above embodiments, and constituent elements in the above embodiments may be arbitrarily combined to achieve another embodiment, which is understood by a person skilled in the art with ease. Therefore, such modifications and other embodiments are also included in the present disclosure. 
     INDUSTRIAL APPLICABILITY 
     The moving picture coding method and the moving picture decoding method according to the present disclosure is applicable to any multimedia data, and can increase the processing speed of coding and decoding moving pictures without increasing the processing load. The moving picture coding method and the moving picture decoding method according to the present disclosure are useful as a moving picture coding method and a moving picture decoding method in the storage, transmission, communication, and the like using mobile phones, DVD devices, personal computers, and the like, for example.