Image decoding device, image decoding method, and program
An image decoding device includes: a prediction signal generation unit configured to determine whether or not an application condition of Bi-Directional Optical Flow (BDOF) processing is satisfied for each block, generate a prediction signal by executing the BDOF processing in a case where it is determined that the application condition is satisfied, and set the application condition based on a weight coefficient in a case where calculation is performed using pixel values of two reference frames or values calculated from the pixel values in the BDOF processing such that the application condition includes a condition on time distances between the two reference frames and a target frame.
1. An image decoding device comprising:
a memory storing instructions; and
one or more processors configured to:
determine whether or not an application condition of BDOF (Bi-Directional Optical Flow) processing is satisfied for each block based on:
a first time distance between a target frame and a first reference frame of two reference frames being equal to a second time distance between the target frame and a second reference frame of the two reference frames, and
a first weight coefficient of the first reference frame and a second weight coefficient of the second reference frame;
divide each block into sub-blocks; and
if it is determined that the application condition of BDOF processing is satisfied, perform the BDOF processing to generate a prediction signal for each of the sub-blocks.
2. An image decoding method comprising:
storing instructions in a memory;
determining whether or not an application condition of BDOF processing is satisfied for each block based on:
a first time distance between a target frame and a first reference frame of two reference frames being equal to a second time distance between the target frame and a second reference frame of the two reference frames, and
a first weight coefficient of the first reference frame and a second weight coefficient of the second reference frame;
dividing each block into sub-blocks; and
if it is determined that the application condition of BDOF processing is satisfied, performing the BDOF processing to generate a prediction signal for each of the sub-blocks.
3. A non-transitory computer readable medium with instructions thereon that when executed by one or more processors of an image decoding device, cause the processor program causing a computer to function as an image decoding device, the image decoding device being configured to:
determining whether or not an application condition of BDOF processing is satisfied for each block based on:
a first time distance between a target frame and a first reference frame of two reference frames being equal to a second time distance between the target frame and a second reference frame of the two reference frames, and
a first weight coefficient of the first reference frame and a second weight coefficient of the second reference frame;
dividing each block into sub-blocks; and
if it is determined that the application condition of BDOF processing is satisfied, performing the BDOF processing to generate a prediction signal for each of the sub-blocks.