The X pixel position in an output frame to be transformed. The Y pixel position in an output frame to be transformed. A scale of 0.5 means a magnification of two from input to output. Shifts are always along the axes of the image.
Positive values shift the image to the right.
Shifts are always along the axes of the image. Positive values shift the image upwards. The name of a text file containing the coefficients for the geometrical transformation to be applied. These geometric transformations are always applied before the shifts, rotations and scale changes specified by other parameters. The frame in which the shifts are applied, or to put it another way, whether to apply the rotation before the shifts.