A method for video decoding in a decoder, comprising: decoding prediction information of a current block in a current picture from a coded video bitstream, the prediction information being indicative of an affine model, the current block including two or more control points; determining a motion vector for each of the two or more control points based on a corresponding motion vector predictor for the respective control point, the corresponding motion vector predictor for the respective control point being a first predictor of a plurality of candidate motion vector predictors in a candidate list and meeting a constraint that is associated with a motion vector of the corresponding motion vector predictor; determining parameters of an affine model based on the determined motion vectors of the two or more control points, the parameters of the affine model being used to transform between the current block and a reference block in a reference picture that has been reconstructed; and reconstructing at least a sample of the current block according to the affine model, wherein the constraint indicates: a fifth limit from a width picture boundary for a first luma sample position to which a motion vector associated with a control point of the corresponding motion vector predictor of the one of the two or more control points refers, the fifth limit being defined by a first number of luma samples beyond the width picture boundary of the current picture; and a sixth limit from a height picture boundary for a second luma sample position to which the motion vector associated with the control point of the corresponding motion vector predictor of the one of the two or more control points refers, the sixth limit being defined by a second number of luma samples beyond the height picture boundary of the current picture, wherein the fifth limit is a predefined first percentage of a width of the current picture, and the sixth limit is a predefined second percentage of a height of the current picture. decoding prediction information of a current block in a current picture from a coded video bitstream, the prediction information being indicative of an affine model, the current block including two or more control points; determining a motion vector for each of the two or more control points based on a corresponding motion vector predictor for the respective control point, the corresponding motion vector predictor for the respective control point being a first predictor of a plurality of candidate motion vector predictors in a candidate list and meeting a constraint that is associated with a motion vector of the corresponding motion vector predictor; determining parameters of an affine model based on the determined motion vectors of the two or more control points, the parameters of the affine model being used to transform between the current block and a reference block in a reference picture that has been reconstructed; and reconstructing at least a sample of the current block according to the affine model, wherein the constraint indicates: a fifth limit from a width picture boundary for a first luma sample position to which a motion vector associated with a control point of the corresponding motion vector predictor of the one of the two or more control points refers, the fifth limit being defined by a first number of luma samples beyond the width picture boundary of the current picture; and a sixth limit from a height picture boundary for a second luma sample position to which the motion vector associated with the control point of the corresponding motion vector predictor of the one of the two or more control points refers, the sixth limit being defined by a second number of luma samples beyond the height picture boundary of the current picture, wherein the fifth limit is a predefined first percentage of a width of the current picture, and the sixth limit is a predefined second percentage of a height of the current picture. a fifth limit from a width picture boundary for a first luma sample position to which a motion vector associated with a control point of the corresponding motion vector predictor of the one of the two or more control points refers, the fifth limit being defined by a first number of luma samples beyond the width picture boundary of the current picture; and a sixth limit from a height picture boundary for a second luma sample position to which the motion vector associated with the control point of the corresponding motion vector predictor of the one of the two or more control points refers, the sixth limit being defined by a second number of luma samples beyond the height picture boundary of the current picture, wherein the fifth limit is a predefined first percentage of a width of the current picture, and the sixth limit is a predefined second percentage of a height of the current picture.