Coding method and apparatus with candidate motion vectors

A moving picture coding apparatus that codes a current block of a picture, the moving picture coding apparatus comprising:

• a first deriver configured to derive a first candidate having a first motion vector predictor derived from a first motion vector that has been used to code a first block;
• a determiner configured to determine whether a total number of one or more candidates having the first candidate is less than a predetermined maximum candidate number;
• a second deriver configured to derive a second candidate having a second motion vector predictor when the total number of the one or more candidates having the first candidate is less than the predetermined maximum candidate number;
• and
• a coder configured to code an index corresponding to a candidate having a motion vector predictor,
• wherein the candidate is one of a plurality of candidates having the first candidate and the second candidate, and
• the predetermined maximum candidate number is fixed for all blocks in a slice of the picture.

A moving picture coding apparatus that codes a current block of a picture, the moving picture coding apparatus comprising:

• a processor;
• and
• a memory including instructions that, when executed by the processor, cause the processor to perform operations including:
• deriving a first candidate having a first motion vector predictor derived from a first motion vector that has been used to code a first block;
• determining whether a total number of one or more candidates having the first candidate is less than a predetermined maximum candidate number;
• deriving a second candidate having a second motion vector predictor when the total number of the one or more candidates having the first candidate is less than the predetermined maximum candidate number;
• and
• coding an index corresponding to a candidate having a motion vector predictor,
• wherein the candidate is one of a plurality of candidates having the first candidate and the second candidate, and
• the predetermined maximum candidate number is fixed for all blocks in a slice of the picture.