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: An image coding method includes: generating a first flag indicating whether or not a motion vector predictor is to be selected from among one or more motion vector predictor candidates; generating a second flag indicating whether or not a motion vector predictor is to be selected from among the one or more motion vector predictor candidates in coding a current block to be coded in a predetermined coding mode, when the first flag indicates that a motion vector predictor is to be selected; and generating a coded signal in which the first flag and the second flag are included in header information, when the first flag indicates that a motion vector predictor is to be selected.

Abstract: By the moving picture coding method and the moving picture decoding method, it is possible to improve coding efficiency. The moving picture coding apparatus includes a merge block candidate calculation unit that (i) specifies merge block candidates at merge mode, by using colpic information such as motion vectors and reference picture index values of neighbor blocks of a current block to be coded and a motion vector and the like of a collocated block of the current block which are stored in a colPic memory, and (ii) generates a combined merge block by using the merge block candidates.

Abstract: An image coding method includes coding a motion vector difference indicating a difference between the motion vector and a predicted motion vector, wherein the coding includes: coding a first portion that is a part of a first component which is one of a horizontal component and a vertical component of the motion vector difference; coding a second portion that is a part of a second component which is different from the first component and is the other one of the horizontal component and the vertical component; coding a third portion that is a part of the first component and is different from the first portion; coding a fourth portion that is a part of the second component and is different from the second portion; and generating a code string which includes the first portion, the second portion, the third portion, and the fourth portion in the stated order.

Abstract: A moving picture coding apparatus for coding a current block from among blocks in a picture is provided. A motion vector predictor candidate list, having a fixed size, is generated, with the motion vector predictor candidate list including first and second candidates. The motion vector predictor candidate list is generated by: deriving the first candidate from a first motion vector used to code a first block, with the first block being adjacent to the current block; and deriving the second candidate that has a second motion vector that is a non-zero value vector based on an X-Y axis of a fixed offset value, with the second motion vector not being derived by coding a block adjacent to the current block and the fixed offset value being a non-zero value that is added in a picture header and commonly used for the blocks in the picture.

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: 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: A moving picture decoding apparatus for decoding a current block of a picture is provided. A motion vector candidate list includes motion vector candidates. Each motion vector candidate includes a value. 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 value of the first candidate and the value of the second candidate. An index identifying a motion vector candidate from the motion vector candidate list is decoded, and the current block is generated using the identified motion vector candidate. The value of the first candidate is higher than the value of the second candidate, and the value is based on a number of times the candidate is selected as a motion vector predictor for neighboring blocks.

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 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.

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 method of encoding video including: writing a plurality of predetermined buffer descriptions into a sequence parameter set of a coded video bitstream; writing a plurality of updating parameters into a slice header of the coded video bitstream for selecting and modifying one buffer description out of the plurality of buffer descriptions; and encoding a slice into the coded video bitstream using the slice header and the modified buffer description.

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: An image coding method includes: performing context arithmetic coding to consecutively code (i) first information indicating whether or not to perform sample adaptive offset (SAO) processing for a first region of an image and (ii) second information indicating whether or not to use, in the SAO processing for the first region, information on SAO processing for a region other than the first region, the context arithmetic coding being arithmetic coding using a variable probability, the SAO processing being offset processing on a pixel value; and performing bypass arithmetic coding to code other information which is information on the SAO processing for the first region and different from the first information or the second information, after the first information and the second information are coded, the bypass arithmetic coding being arithmetic coding using a fixed probability.

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: By the moving picture coding method and the moving picture decoding method, it is possible to improve coding efficiency. The moving picture coding apparatus includes a merge block candidate calculation unit that (i) specifies merge block candidates at merge mode, by using colpic information such as motion vectors and reference picture index values of neighbor blocks of a current block to be coded and a motion vector and the like of a collocated block of the current block which are stored in a colPic memory, and (ii) generates a combined merge block by using the merge block candidates.

Abstract: With an image coding method which allows reduction of processing loads, when pictures included in a video signal are classified into layers so as to belong to their respective layers, a picture that belongs to the second layer that is located in a range restricted according to the first layer to which a current picture to be coded that is one of the pictures belongs, is referred to as a reference picture for the current picture, and the current picture is coded based on the reference 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.

Abstract: An image decoding method decodes a coded stream which includes processing units and a header of the processing units, and which is generated by coding a moving picture using inter prediction. The processing units includes at least one processing unit divided in a hierarchy, the hierarchy including a highest hierarchical layer in which a coding unit exists as a largest processing unit and a lower hierarchical layer in which a prediction unit exists. The method includes identifying, by parsing hierarchy depth information stored in the header and indicating a hierarchical layer higher than a lowest hierarchical layer in which a smallest prediction unit exits, a hierarchical layer which is indicated by the hierarchy depth information or a hierarchical layer higher than the indicated hierarchical layer. The hierarchical layer includes a prediction unit in which a reference index is stored. The prediction unit is decoded using the reference index.