Moving picture coding and decoding method with replacement and temporal motion vectors
A moving picture coding method includes: coding a coding target block using a motion vector; generating motion vector predictors; and coding the motion vector using one of the motion vector predictors generated in the generating of the motion vector predictors. In the generating of the motion vector predictors, a replacement vector which replaces a temporal motion vector predictor is added to the motion vector predictors when it is impossible to obtain the temporal motion vector predictor from a block which is included in a coded picture different from the coding target picture and corresponds to the coding target block.
1. A moving picture coding method for performing inter prediction coding on a coding target block included in a coding target picture, the moving picture coding method comprising:
coding the coding target block using a motion vector;
generating a plurality of motion vector predictors; and
coding the motion vector using one of the plurality of motion vector predictors generated in the generating,
wherein, in the generating, a replacement vector which replaces a temporal motion vector predictor is included in the plurality of motion vector predictors when obtaining the temporal motion vector predictor from a block, which is included in a coded picture different from the coding target picture and corresponds to the coding target block, is prohibited, and
in the generating, (i) whether or not obtainment of the temporal motion vector predictor from a block corresponding to the coding target block included in the coded target picture is prohibited is determined, and (ii) when it is determined that the obtainment of the temporal motion vector predictor block is prohibited, a motion vector having a motion quantity of 0 is included, as the replacement vector, in the plurality of motion vector predictors.
2. A moving picture coding apparatus for performing inter prediction coding on a coding target block included in a coding target picture, the moving picture coding apparatus comprising:
an image coder configured to code the coding target block using a motion vector;
a motion vector predictor candidate generating unit configured to generate a plurality of motion vector predictors; and
a motion vector coder configured to code the motion vector using one of the plurality of motion vector predictors generated by the motion vector predictor candidate generating unit,
wherein motion vector predictor candidate generating unit is configured to include a replacement vector which replaces a temporal motion vector predictor in the plurality of motion vector predictors when obtaining the temporal motion vector predictor from a block, which is included in a coded picture different from the coding target picture and corresponds to the coding target block, is prohibited, and
motion vector predictor candidate generating unit is configured to (i) determine whether or not obtainment of the temporal motion vector predictor from a block corresponding to the coding target block included in the coded target picture is prohibited, and (ii) when it is determined that the obtainment of the temporal motion vector predictor block is prohibited, include a motion vector having a motion quantity of 0, as the replacement vector, in the plurality of motion vector predictors.