Moving picture coding method, moving picture coding apparatus, moving picture decoding method, moving picture decoding apparatus, and moving picture coding and decoding apparatus

A decoding apparatus for decoding a current block, the encoding apparatus comprising:

• memory storing instructions;
• and processing circuitry,
• wherein the processing circuitry is configured to perform decoding processing based on the instructions stored in the memory, the decoding processing including:
• deriving a motion vector predictor from a reference block, wherein the reference block is either (i) a neighboring block spatially adjacent to the current block and included in a current picture, or (ii) a collocated block included in a picture other than the current picture;
• adding the derived motion vector predictor to a motion vector predictor list (MVP list);
• and
• decoding the current block by selecting one of the motion vector predictors from the MVP list,
• wherein, when the reference block is a neighboring block spatially adjacent to the current block, deriving the motion vector predictor includes:
• calculating a second motion vector by scaling a first motion vector of the reference block;
• determining whether a magnitude of the second motion vector is within a predetermined magnitude range;
• when the magnitude of the second motion vector is within the predetermined magnitude range, deriving the motion vector predictor as equal to the second motion vector;
• and
• when the magnitude of the second motion vector is not within the predetermined magnitude range, deriving the motion vector predictor by clipping the second motion vector such that the motion vector predictor has a magnitude within the predetermined magnitude range,
• wherein the predetermined magnitude range is based on a 16-bit precision of a motion vector.

A non-transitory computer readable recording medium storing a program that, when executed on a computing device, performs operations comprising:

• deriving a motion vector predictor from a reference block, wherein the reference block is either (i) a neighboring block spatially adjacent to the current block and included in a current picture, or (ii) a collocated block included in a picture other than the current picture;
• adding the derived motion vector predictor to a motion vector predictor list (MVP list);
• and
• decoding the current block by selecting one of the motion vector predictors from the MVP list,
• wherein, when the reference block is a neighboring block spatially adjacent to the current block, deriving the motion vector predictor includes:
• calculating a second motion vector by scaling a first motion vector of the reference block;
• determining whether a magnitude of the second motion vector is within a predetermined magnitude range;
• when the magnitude of the second motion vector is within the predetermined magnitude range, deriving the motion vector predictor as equal to the second motion vector;
• and
• when the magnitude of the second motion vector is not within the predetermined magnitude range, deriving the motion vector predictor by clipping the second motion vector such that the motion vector predictor has a magnitude within the predetermined magnitude range,
• wherein the predetermined magnitude range is based on a 16-bit precision of a motion vector.