Method and apparatus for video coding

An apparatus for encoding video, the apparatus comprising:

• a memory storing instructions;
• and
• a processor in communication with the memory, wherein, when the processor executes the instructions, the processor is configured to cause the apparatus to:
• determine whether to apply a prediction refinement with optical flow (PROF) to an affine coded block;
• and
• in response to determining to apply the PROF to the affine coded block:
• generate spatial gradients gx(i,j) and gy(i,j) at a sample location (i,j) in the affine coded block,
• generate a prediction refinement ΔI(i,j) based on the spatial gradients gx(i,j) and gy (i,j), and
• add the prediction refinement ΔI(i,j) to a prediction sample I(i,j) to generate a refined prediction sample.

A non-transitory computer readable storage medium storing instructions, wherein, when the instructions are executed by a processor, the instructions are configured to cause the processor to:

• determine whether to apply a prediction refinement with optical flow (PROF) to an affine coded block;
• and
• in response to determining to apply the PROF to the affine coded block:
• generate spatial gradients gx(i,j) and gy(i,j) at a sample location (i,j) in the affine coded block,
• generate a prediction refinement ΔI(i,j) based on the spatial gradients gx(i,j) and gy(i,j), and
• add the prediction refinement ΔI(i,j) to a prediction sample I(i,j) to generate a refined prediction sample.