Image coding method, image decoding method, image coding apparatus, image decoding apparatus, and image coding and decoding apparatus

An image decoding apparatus which decodes a plurality of blocks included in a plurality of pictures of an image, the image decoding apparatus comprising:

• an addition unit configured to (i) determine, for each of one or more associated blocks, whether or not to add a motion vector of the associated block to a list, and (ii) add the motion vector of the associated block to the list when determining that the motion vector of the associated block is to be added to the list, the one or more associated blocks being one or more blocks included in the plurality of blocks;
• a selection unit configured to select, from the list, a motion vector which is to be merged to a current block that is a block which is included in the plurality of blocks and is different from the one or more associated blocks;
• and
• a decoding unit configured to (i) merge, to the current block, the motion vector selected by the selection unit, and (ii) decode the current block using the merged motion vector as a motion vector of the current block,
• wherein the addition unit is configured to determine that the motion vector of the associated block is not to be added to the list when an associated picture and an associated reference picture match temporally or when a current picture and a current reference picture match temporally, the associated picture being a picture including the associated block, the associated reference picture being a picture which is referred to using the motion vector of the associated block in decoding of the associated block, the current picture being a picture including the current block, and the current reference picture being a picture which is referred to using the motion vector of the current block in the decoding of the current block.