Video coding/decoding system, video coding/decoding method, and storage medium

1. A video coding/decoding system, comprising:

a video coding apparatus including

a first reference picture list storing unit configured to store picture information of pictures,

a first motion vector information storing unit configured to store motion vector information including motion vectors of blocks that are spatially or temporally adjacent to a target block to be processed, and reference picture identifiers indicating pictures that the motion vectors refer to, and

a first vector predictor generating unit configured to scale a vector predictor candidate of the target block based on the picture information and the motion vector information and to correct the scaled vector predictor candidate by subtracting a predetermined value from an absolute value of the scaled vector predictor,

wherein the first vector predictor generating unit includes

a first scaling factor calculation unit configured to calculate a scaling factor having a predetermined precision after a decimal point based on the picture information and the motion vector information, and

a first scaling operation unit configured to scale the vector predictor candidate by the scaling factor and to correct the scaled vector predictor candidate by subtracting the predetermined value from the absolute value of the scaled vector predictor,

wherein the first scaling operation unit includes

a first scaling unit configured to multiply the vector predictor candidate by the scaling factor to scale the vector predictor candidate and increase a precision after the decimal point of the scaled vector predictor candidate to the predetermined precision after the decimal point,

a first correcting unit configured to correct the scaled vector predictor candidate by subtracting the predetermined value from the absolute value of the scaled vector predictor, and

a first adjusting unit configured to round the scaled and corrected vector predictor candidate to nearest integers; and

a video decoding apparatus including

a second reference picture list storing unit configured to store the picture information of the pictures,

a second motion vector information storing unit configured to store the motion vector information including the motion vectors of the blocks that are spatially or temporally adjacent to the target block and the reference picture identifiers indicating the pictures that the motion vectors refer to, and

a second vector predictor generating unit configured to scale the vector predictor candidate for the motion vector of the target block based on the picture information and the motion vector information and to correct the scaled vector predictor candidate by subtracting the predetermined value from the absolute value of the scaled vector predictor,

wherein the second vector predictor generating unit includes

a second scaling factor calculation unit configured to calculate the scaling factor having the predetermined precision after the decimal point based on the picture information and the motion vector information, and

a second scaling operation unit configured to scale the vector predictor candidate by the scaling factor and to correct the scaled vector predictor candidate by subtracting the predetermined value from the absolute value of the scaled vector predictor,

wherein the second scaling operation unit includes

a second scaling unit configured to multiply the vector predictor candidate by the scaling factor to scale the vector predictor candidate and increase a precision after the decimal point of the scaled vector predictor candidate to the predetermined precision after the decimal point,

a second correcting unit configured to correct the scaled vector predictor candidate by subtracting the predetermined value from the absolute value of the scaled vector predictor; and

a second adjusting unit configured to round the scaled and corrected vector predictor candidate to nearest integers.

2. A method performed by a video coding/decoding system, the method comprising:

scaling a vector predictor candidate of a target block to be processed, based on picture information of pictures and motion vector information including motion vectors of blocks that are spatially or temporally adjacent to the target block and reference picture identifiers indicating pictures that the motion vectors refer to;

correcting the scaled vector predictor candidate by subtracting a predetermined value from an absolute value of the scaled vector predictor,

wherein the scaling includes

calculating a scaling factor based on the picture information and the motion vector information, and

scaling the vector predictor candidate by the scaling factor;

wherein the scaling factor has a predetermined precision after a decimal point;

wherein in the scaling, the vector predictor candidate is multiplied by the scaling factor to scale the vector predictor candidate and to increase a precision after the decimal point of the scaled vector predictor candidate to the predetermined precision after the decimal point; and

wherein the vector predictor candidate scaled by the scaling factor and corrected by the predetermined amount is rounded to nearest integers;

scaling the vector predictor candidate of the target block, based on the picture information and the motion vector information;

correcting the scaled vector predictor candidate by subtracting the predetermined value from the absolute value of the scaled vector predictor;

calculating the scaling factor having the predetermined precision after the decimal point based on the picture information and the motion vector information; and

scaling the vector predictor candidate by the scaling factor and correcting the scaled vector predictor candidate by subtracting the predetermined value from the absolute value of the scaled vector predictor,

wherein the scaling of the vector predictor candidate includes:

multiplying the vector predictor candidate by the scaling factor to scale the vector predictor candidate and increase a precision after the decimal point of the scaled vector predictor candidate to the predetermined precision after the decimal point;

correcting the scaled vector predictor candidate by subtracting the predetermined value from the absolute value of the scaled vector predictor; and

rounding the scaled and corrected vector predictor candidate to nearest integers.

3. A non-transitory computer-readable storage medium storing a program code for causing a video coding/decoding system to perform a method comprising:

scaling a vector predictor candidate of a target block to be processed, based on picture information of pictures and motion vector information including motion vectors of blocks that are spatially or temporally adjacent to the target block and reference picture identifiers indicating pictures that the motion vectors refer to;

correcting the scaled vector predictor candidate by subtracting a predetermined value from an absolute value of the scaled vector predictor,

wherein the scaling includes

calculating a scaling factor based on the picture information and the motion vector information, and

scaling the vector predictor candidate by the scaling factor;

wherein the scaling factor has a predetermined precision after a decimal point;

wherein in the scaling, the vector predictor candidate is multiplied by the scaling factor to scale the vector predictor candidate and to increase a precision after the decimal point of the scaled vector predictor candidate to the predetermined precision after the decimal point; and

wherein the vector predictor candidate scaled by the scaling factor and corrected by the predetermined amount is rounded to nearest integers;

scaling the vector predictor candidate of the target block, based on the picture information and the motion vector information;

correcting the scaled vector predictor candidate by subtracting the predetermined value from the absolute value of the scaled vector predictor;

calculating the scaling factor having the predetermined precision after the decimal point based on the picture information and the motion vector information; and

scaling the vector predictor candidate by the scaling factor and correcting the scaled vector predictor candidate by subtracting the predetermined value from the absolute value of the scaled vector predictor,

wherein the scaling of the vector predictor candidate includes:

multiplying the vector predictor candidate by the scaling factor to scale the vector predictor candidate and increase a precision after the decimal point of the scaled vector predictor candidate to the predetermined precision after the decimal point;

correcting the scaled vector predictor candidate by subtracting the predetermined value from the absolute value of the scaled vector predictor; and

rounding the scaled and corrected vector predictor candidate to nearest integers.