Abstract: A picture coding method includes: performing a first derivation process for deriving a first merging candidate which includes a candidate set of a prediction direction, a motion vector, and a reference picture index for use in coding of a current block; performing a second derivation process for deriving a second merging candidate; selecting a merging candidate to be used in the coding of the current block from among the first and second merging candidates; and attaching an index for identifying the selected merging candidate to the bitstream; wherein the first derivation process is performed so that a total number of the first merging candidates does not exceed a predetermined number, and the second derivation process is performed when the total number of the first merging candidates is less than a predetermined maximum number of merging candidates.

Abstract: A moving picture coding includes: coding a first flag indicating whether or not temporal motion vector prediction is used; when the first flag indicates that the temporal motion vector prediction is used: coding a first parameter for calculating the temporal predictive motion vector; wherein when the first flag indicates that the temporal motion vector prediction is not used, the first parameter is not coded.

Abstract: A picture coding method includes: performing a first derivation process for deriving a first merging candidate which includes a candidate set of a prediction direction, a motion vector, and a reference picture index for use in coding of a current block; performing a second derivation process for deriving a second merging candidate; selecting a merging candidate to be used in the coding of the current block from among the first and second merging candidates; and attaching an index for identifying the selected merging candidate to the bitstream; wherein the first derivation process is performed so that a total number of the first merging candidates does not exceed a predetermined number, and the second derivation process is performed when the total number of the first merging candidates is less than a predetermined maximum number of merging candidates.

Abstract: An image decoding method includes: dividing a current block into sub-blocks; deriving, for each sub-block, one or more prediction information candidates; obtaining an index; and decoding the current block using the prediction information candidate selected by the index.

Abstract: A moving picture coding method includes: making a determination as to whether or not to code all blocks in a current picture in the skip mode; setting, based on a result of the determination, a first flag indicating whether or not a temporally neighboring block is to be referenced, a value of a parameter for determining a total number of merging candidates, and a second flag for each block included in the current picture, the second flag indicating whether or not the block is to be coded in the skip mode; calculating, as a merging candidate, a neighboring block usable for merging; and coding an index which indicates a merging candidate to be used for coding of the current block and attaching the coded index to a bitstream.

Abstract: Obtaining one or more motion vector predictor candidates includes: (a1) generating a motion vector predictor candidate, based on motion vectors of first adjacent blocks adjacent to a block to be processed in a first direction; and (a2) generating a motion vector predictor candidate, based on motion vectors of second adjacent blocks adjacent to the block to be processed in a second direction, and step (a2) includes: determining whether the first adjacent blocks include an inter-predicted block; and searching for a motion vector on which scaling processing can be performed from among the motion vectors of the second adjacent blocks when it is determined that the first adjacent blocks do not include an inter-predicted block, and executing, when the motion vector on which scaling processing can be performed is obtained in the search, scaling processing on the motion vector obtained in the search.

Abstract: A method for transmitting a bitstream via a network is provided. The bitstream is for coding a current block and is generated by: deriving a first candidate from a first motion vector that has been used to code a first block; coding a first index identifying a reference picture to be used for coding the current block; deriving a second candidate having a second motion vector that includes a non-zero value, which is assigned to the reference picture; and coding a second index identifying a selected candidate to be used for coding the current block. The second motion vector is not derived by coding a block adjacent to the current block, and the non-zero value is assigned by offset values which include an OffsetX and an OffsetY and which are located in a picture header.

Abstract: A transmitting method for transmitting a bitstream to a terminal is provided. The bit stream is generated by coding a current block of a picture and has an index for identifying a motion vector candidate from a motion vector candidate list. The motion vector candidate list is generated and includes motion vector candidates and a value for each motion vector candidate. A second candidate is arranged before a first candidate in the motion vector candidate list. The first candidate is sorted before the second candidate in the motion vector candidate list based on the values of the first and second candidates. The value of the first candidate is higher than the value of the second candidate. For each motion vector candidate, the value is based on a number of times the motion vector candidate is selected as a motion vector predictor for neighboring blocks.

Abstract: Various embodiments for transmitting a bitstream via a network are provided. The bitstream includes an index identifying a motion vector from a candidate list. The candidate list is generated by: adding, when a motion vector used for coding a first block spatially adjacent to the current block is useable for coding the current block, one or more first candidates to the candidate list; adding a second candidate to the candidate list, with the second candidate being derived based on a motion vector used for coding a second block within a first collocated picture; and adding a third candidate to the candidate list until a number of the plurality of candidates in the candidate list reaches a maximum number, with the third candidate being derived based on a motion vector used for coding a third block within a second collocated picture.

Abstract: An image coding method includes: deriving a candidate for a motion vector of a current block from a co-located motion vector; adding the candidate to a list; selecting the motion vector of the current block from the list; and coding the current block, wherein the deriving includes: deriving the candidate by a first derivation scheme in the case of determining that each of a current reference picture and a co-located reference picture is a long-term reference picture; and deriving the candidate by a second derivation scheme in the case of determining that each of the current reference picture and the co-located reference picture is a short-term reference picture.

Abstract: An image coding method includes: writing, into a sequence parameter set, buffer description defining information for defining a plurality of buffer descriptions; writing, into the sequence parameter set, reference list description defining information for defining a plurality of reference list descriptions corresponding to the buffer descriptions; and writing, into a first header of each processing unit which is included in a coded bitstream, buffer description selecting information for specifying a selected buffer description.

Abstract: A moving picture coding includes: coding a first flag indicating whether or not temporal motion vector prediction is used; when the first flag indicates that the temporal motion vector prediction is used: coding a first parameter for calculating the temporal predictive motion vector; wherein when the first flag indicates that the temporal motion vector prediction is not used, the first parameter is not coded.

Abstract: A moving picture coding apparatus, method, and medium for coding a current block of a picture are provided. A motion vector candidate list is generated that includes motion vector candidates and, for each of the motion vector candidates, a value. The motion vector candidates include a first candidate and a second candidate. The second candidate is arranged before the first candidate in the motion vector candidate list. The first candidate is sorted before the second candidate in the motion vector candidate list based on the value of the first candidate and the value of the second candidate. The value of the first candidate is higher than the value of the second candidate. For each of the motion vector candidates, the value is based on a number of times the motion vector candidate is selected as a motion vector predictor for neighboring blocks.

Abstract: A moving picture coding apparatus for coding a current block is provided. A first candidate is derived from a first motion vector that has been used to code a first block, and it is determined whether a total number of candidates including the first candidate is less than a maximum candidate number. A second candidate having a second motion vector is derived when the total number of the candidates is less than the maximum candidate number, with the second motion vector including a zero vector. A candidate is selected from a plurality of candidates including the first candidate and the second candidate, and the current block is decoded using the selected candidate.

Abstract: Obtaining one or more motion vector predictor candidates includes: (a1) generating a motion vector predictor candidate, based on motion vectors of first adjacent blocks adjacent to a block to be processed in a first direction; and (a2) generating a motion vector predictor candidate, based on motion vectors of second adjacent blocks adjacent to the block to be processed in a second direction, and step (a2) includes: determining whether the first adjacent blocks include an inter-predicted block; and searching for a motion vector on which scaling processing can be performed from among the motion vectors of the second adjacent blocks when it is determined that the first adjacent blocks do not include an inter-predicted block, and executing, when the motion vector on which scaling processing can be performed is obtained in the search, scaling processing on the motion vector obtained in the search.

Abstract: A moving picture decoding apparatus, method, and medium for decoding a current block are provided. A first candidate is derived from a first motion vector that has been used to decode a first block. The first block is adjacent to the current block. A first index identifying a reference picture to be selected for decoding the current block is decoded. A second candidate having a second motion vector that includes a non-zero value is derived. The non-zero value is assigned to the reference picture. A selected candidate is selected from a plurality of candidates, including the first candidate and the second candidate. A second index identifying the selected candidate is decoded. The current block is decoded using the selected candidate. The second candidate includes the non-zero value of the reference picture, with the reference picture being selected from a plurality of referable reference pictures.

Abstract: Various embodiments for calculating a motion vector predictor for decoding a motion vector of a current block are provided. The motion vector is selected from a candidate list. When a motion vector used for coding a first block spatially adjacent to the current block in a current picture is useable for coding the current block, one or more first candidates is added to the candidate list based on the motion vector used for coding the first block. A second candidate is added to the candidate list based on a motion vector used for coding a second block within a first collocated picture. When a total number of available candidates in the candidate list is less than a predetermined number, a third candidate is added to the candidate list based on a motion vector used for coding a third block within a second collocated picture.

Abstract: The image decoding method includes: determining a context for use in a current block to be processed, from among a plurality of contexts; and performing arithmetic decoding on a bit sequence corresponding to the current block, using the determined context, wherein in the determining: the context is determined under a condition that control parameters of neighboring blocks of the current block are used, when the signal type is a first type, the neighboring blocks being a left block and an upper block of the current block; and the context is determined under a condition that the control parameter of the upper block is not used, when the signal type is a second type, and the second type is one of “ref_idx_l0” and “ref_idx_l1”.

Abstract: An image coding method includes: writing, into a sequence parameter set, buffer description defining information for defining a plurality of buffer descriptions; writing, into the sequence parameter set, reference list description defining information for defining a plurality of reference list descriptions corresponding to the buffer descriptions; and writing, into a first header of each processing unit which is included in a coded bitstream, buffer description selecting information for specifying a selected buffer description.

Abstract: A decoding method and apparatus are provided. A first candidate having a first motion vector that has been used to decode a first block, a first prediction direction that corresponds to the first motion vector, and a first reference picture index that identifies a first reference picture is derived. A second candidate having a second motion vector that has been used to decode a second block, a second prediction direction that corresponds to the second motion vector, and a second reference picture index that identifies a second reference picture is derived. When a total number of candidates is less than a maximum number, a third candidate is derived by combining the first motion vector and the first reference picture index for the first prediction direction of the first candidate and the second motion vector and the second reference picture index for the second prediction direction of the second candidate.