Method and apparatus for video coding using a subblock-based affine motion model

An apparatus for video decoding, comprising:

• processing circuitry configured to:
• decode coding information of a current block (CB) from a coded video bitstream, the coding information indicating that, the CB is coded with a subblock-based affine motion model, the subblock-based affine motion model including affine parameters that are based on multiple control point (CP) motion vectors (MVs) (CPMVs) for the CB and based on at least one of a height or a width of the CB, the CB including an affine subblock having a subblock MV;
• determine, based on the coding information, whether to select a subblock characteristic for generating a prediction for a sample in the affine subblock based on the subblock MV;
• in response to selecting the subblock characteristic, determine the subblock characteristic based on at least one of the affine parameters, the subblock characteristic indicating one of:
• (i) a subblock size used for generating the prediction for the sample and (ii) an interpolation filter type for the affine subblock;
• and
• reconstruct the sample in the affine subblock based on the determined subblock characteristic, wherein
• the subblock characteristic is determined based on a comparison of an absolute value of the at least one of the affine parameters to one of:
• (i) a threshold and (ii) a pre-defined range, and
• the interpolation filter type includes a first interpolation filter having a first length or a second interpolation filter having a second length, the first length being less than the second length.