Methods and apparatuses for prediction refinement with optical flow

Abstract

Methods, apparatuses, and non-transitory computer-readable storage mediums are provided for encoding a video signal. A method may include obtain a first reference picture associated with a video block in a current picture within the video signal and a first motion vector (MV) from the video block in the current picture to a reference block in the first reference picture; obtain first prediction samples I(i,j) of the video block generated from the reference block in the first reference picture; control internal bit-depths of internal prediction refinement with optical flow (PROF) parameters; obtain a prediction refinement value for the first prediction sample I(i,j); obtain second prediction samples I'(i,j) associated with a second MV and a corresponding prediction refinement value for a second prediction sample I′(i,j); and obtain a final prediction sample of the video block based on the first prediction sample I(i,j), the second prediction sample I′(i,j), and the prediction refinement values.