Video decoding apparatus and video coding apparatus
A load in processing of searching for a motion vector is reduced. In order to solve the problem described above, a motion vector derivation apparatus according to one aspect of the present invention that derives a motion vector to be referred to for generating a prediction image to be used for coding or decoding of a video includes a motion vector search unit configured to search for a motion vector on a prediction unit basis through matching processing. The motion vector search unit is configured to stop search of the motion vector, depending on whether or not a conditional expression according to a pixel bit-depth is satisfied.
1. A motion vector derivation apparatus to derive a motion vector for each of multiple subblocks, the motion vector derivation apparatus comprising:
a matching prediction processing circuit that derives a first prediction block by using a first reference picture and a second prediction block by using a second reference picture; wherein
the matching prediction processing circuit derives a sum of an absolute difference between the first prediction block, which is defined by a first location, and the second prediction block, which is defined by a second location,
the matching prediction processing circuit derives an initial motion vector by using the sum of the absolute difference,
the matching prediction processing circuit derives the motion vector of a subblock by using the initial motion vector, and
the sum of the absolute difference is derived by correcting values of the first prediction block and the second prediction block with a shift value corresponding to a bit depth value.
2. A motion vector derivation method to derive a motion vector for each of multiple subblocks, the motion vector derivation method comprising:
deriving a first prediction block by using a first reference picture and a second prediction block by using a second reference picture;
deriving a sum of an absolute difference between the first prediction block, which is defined by a first location, and the second prediction block, which is defined by a second location;
deriving an initial motion vector by using the sum of the absolute difference; and
deriving the motion vector of a subblock by using the initial motion vector; wherein
the sum of the absolute difference is derived by correcting values of the first prediction block and the second prediction block with a shift value corresponding to a bit depth value.
3. A video decoding apparatus comprising:
a motion vector derivation apparatus according to claim 1 ; and
a prediction image generator to generate a prediction image with reference to a motion vector.
4. A video coding apparatus comprising:
a motion vector derivation apparatus according to claim 1 ; and
a prediction image generator to generate a prediction image with reference to a motion vector.