Abstract: An image coding method includes: writing, into a sequence parameter set, buffer description defining information for defining a plurality of buffer descriptions; selecting one of the buffer descriptions for each processing unit that is a picture or a slice, and writing buffer description selecting information for specifying the selected buffer description, into a first header of the processing unit which is included in the coded bitstream; and coding the processing unit using the selected buffer description, and the buffer description defining information includes long-term information for identifying, among a plurality of reference pictures indicated in the buffer descriptions, a reference picture to be assigned as a long-term reference picture.

Abstract: A moving picture coding method includes (i) transforming, for each of one or more second processing units included in the first processing unit, a moving picture signal in a spatial domain into a frequency domain coefficient and quantizing the frequency domain coefficient, and (ii) performing arithmetic coding on a luminance CBF flag indicating whether or not a quantized coefficient is included in the second processing unit in which transform and quantization are performed, wherein, in the arithmetic coding, a probability table for use in arithmetic coding is determined according to whether or not the size of the first processing unit is identical to the size of the second processing unit and whether or not the second processing unit has a predetermined maximum size.

Abstract: A video encoding method of performing scalable encoding on input video includes: determining a total number of layers of the scalable encoding to be less than or equal to a maximum layer count determined according to a frame rate; and performing the scalable encoding on the input video to generate a bitstream, using the determined total number of layers.

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: An image decoding method which can improve both image quality and coding efficiency is an image decoding method for decoding a coded stream which includes a plurality of processing units and a header for the processing units, the coded stream being generated by coding a moving picture, the processing units including at least one processing unit layered to be split into a plurality of smaller processing units, the image decoding method including specifying a hierarchical layer having a processing unit in which a parameter necessary for decoding is stored, by parsing hierarchy depth information stored in the header, and decoding the processing unit using the parameter stored in the processing unit located at the specified hierarchical layer.

Abstract: An image coding method includes selecting two or more transform components from among a plurality of transform components that include a translation component and non-translation components, the two or more transform components serving as reference information that represents a reference destination of a current block; coding selection information that identifies the two or more transform components that have been selected from among the plurality of transform components; and coding the reference information of the current block by using reference information of a coded block different from the current block.

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: An image coding method of hierarchically coding a plurality of pictures to generate a bitstream, includes: coding each of the plurality of pictures, which belongs to any one of a plurality of hierarchical layers, with reference to a picture belonging to a hierarchical layer which is same as or lower than a hierarchical layer to which the picture belongs, and without reference to a picture belonging to a hierarchical layer which is higher than the hierarchical layer to which the picture belongs; and generating the bitstream by coding the coded pictures and time information indicating decoding times of the coded pictures. The time information indicates that the decoding times are set at equal intervals for low-layer pictures which are the plurality of pictures other than highest-layer pictures belonging to a highest layer among the plurality of hierarchical layers.

Abstract: A moving picture coding apparatus includes an intra-inter prediction unit which calculates a second motion vector by performing a scaling process on a first motion vector of a temporally neighboring corresponding block, when selectively adding, to a list, a motion vector of each of one or more corresponding blocks each of which is either a block included in a current picture to be coded and spatially neighboring a current block to be coded or a block included in a picture other than the current picture and temporally neighboring the current block, determines whether the second motion vector has a magnitude that is within a predetermined magnitude or not within the predetermined magnitude, and adds the second motion vector to the list when the intra-inter prediction unit determines that the second motion vector has a magnitude that is within the predetermined magnitude range.

Abstract: An image decoding apparatus obtain pieces of coded data that is included in a bitstream and generated by coding tiles. Tile boundary independence information is further obtained from the bitstream, with the tile boundary independence information indicating whether each of boundaries between the tiles is one of a first boundary or a second boundary. The pieces of coded data are decoded to generate image data of the tiles. Image data of a first tile is generated by decoding a first code string included in first coded data with reference to decoding information of a decoded tile when the tile boundary independence information indicates the first boundary, and by decoding the first code string without referring to the decoding information of the decoded tile when the tile boundary independence information indicates the second boundary.

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: 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 coding method includes selecting two or more transform components from among a plurality of transform components that include a translation component and non-translation components, the two or more transform components serving as reference information that represents a reference destination of a current block; coding selection information that identifies the two or more transform components that have been selected from among the plurality of transform components; and coding the reference information of the current block by using reference information of a coded block different from the current block.

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: 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: 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 coding method of hierarchically coding a plurality of pictures to generate a bitstream, includes: coding each of the plurality of pictures, which belongs to any one of a plurality of hierarchical layers, with reference to a picture belonging to a hierarchical layer which is same as or lower than a hierarchical layer to which the picture belongs, and without reference to a picture belonging to a hierarchical layer which is higher than the hierarchical layer to which the picture belongs; and generating the bitstream by coding the coded pictures and time information indicating decoding times of the coded pictures. The time information indicates that the decoding times are set at equal intervals for low-layer pictures which are the plurality of pictures other than highest-layer pictures belonging to a highest layer among the plurality of hierarchical layers.

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.