Image decoding device, image decoding method, and program
An image decoding device includes: a motion vector decoding unit that decodes a motion vector from encoded data; a refinement unit that performs refinement processing to correct the decoded motion vector; and a predictive signal generation unit that generates a predictive signal on the basis of the corrected motion vector outputted from the refinement unit. The predictive signal generation unit determines whether or not to apply BDOF processing for each block, on the basis of information calculated in the course of the refinement processing.
1. An image decoding device, comprising:
a motion vector decoding unit that decodes a motion vector from encoded data;
a refinement unit that performs refinement processing to correct the decoded motion vector, wherein the refinement processing comprises:
performing a search with integer pixel precision using a search image generated from information of the motion vector;
determining a corrected motion vector at integer pixel interval positions through the search; and
performing a motion vector search using non-integer pixel precision;
and
a predictive signal generation unit that generates a predictive signal on the basis of the corrected motion vector outputted from the refinement unit, wherein
the predictive signal generation unit determines whether or not to perform BDOF processing for each block to which the refinement processing is to be performed, on the basis of information calculated in the course of the refinement processing,
the predictive signal generation unit determines, for each of the blocks, that the BDOF processing is not to be performed when a minimum search cost of the refinement processing is less than or equal to a predefined threshold value, and
the predictive signal generation unit provides a decoded image.
2. The image decoding device according to claim 1 , wherein
the predictive signal generation unit determines, for each of the blocks, that the BDOF processing is not to be performed when the difference between the motion vectors before and after the refinement processing is less than or equal to a predefined threshold value.
3. The image decoding device according to claim 1 , wherein
the predictive signal generation unit determines, for each of the blocks, that the BDOF processing is not to be performed when the difference between the motion vectors before and after the refinement processing is zero and when the search cost of a reference block which the motion vectors before the refinement processing and after the refinement processing point to is less than or equal to a predefined threshold value.
4. An image decoding method, comprising the steps of:
(A) decoding a motion vector from encoded data;
(B) performing refinement processing to correct the decoded motion vector, wherein the refinement processing comprises:
performing a search with integer pixel precision using a search image generated from information of the motion vector;
determining a corrected motion vector at integer pixel interval positions through the search; and
performing a motion vector search using non-integer pixel precision;
and
(C) generating a predictive signal on the basis of the corrected motion vector outputted from the refinement unit, wherein
it is determined in the step (C), for each block to which the refinement processing is to be performed, whether or not to perform BDOF processing, on the basis of information calculated in the course of the refinement processing, and
it is determined in the step (C), for each block, that the BDOF processing is not to be performed when a minimum search cost of the refinement processing is less than or equal to a predefined threshold value, and
the predictive signal is a decoded image.
5. A non-transitory computer readable medium having stored thereon instructions comprising executable code, which when executed by at least one processor, cause a computer to execute the steps of:
(A) decoding a motion vector from encoded data;
(B) performing refinement processing to correct the decoded motion vector, wherein the refinement processing comprises:
performing a search with integer pixel precision using a search image generated from information of the motion vector;
determining a corrected motion vector at integer pixel interval positions through the search; and
performing a motion vector search using non-integer pixel precision;
and
(C) generating a predictive signal on the basis of the corrected motion vector outputted from the refinement unit, wherein
it is determined in step (C), for each block to which the refinement processing is to be performed, whether or not to perform BDOF processing, on the basis of information calculated in the course of the refinement processing,
it is determined in the step (C), for each block, that the BDOF processing is not to be performed when a minimum search cost of the refinement processing is less than or equal to a predefined threshold value, and
the predictive signal is a decoded image.