1. A video interpolation method, comprising: analyzing evolution of a scene represented in a video sequence of input frames; and computing output pixels of an output frame having a time position intermediate between time positions of the input frames, by combining respective input pixels of the input frames, wherein at least three interpolation modes are provided for computing the output pixels, the interpolation modes including: a first mode in which the combined input pixels for an output pixel are selected based on a position of the output pixel in the output frame and a default interpolation vector; a second mode in which said combined input pixels are selected based on said output pixel position and at least one first interpolation vector determined for the output pixel when analyzing scene evolution; and a third mode in which said combined input pixels are selected based on said output pixel position and at least one second interpolation vector that is intermediate between the default interpolation vector and a respective first interpolation vector determined for said output pixel when analyzing scene evolution, and wherein the method further comprises: while one of the first and second interpolation modes is used at an output pixel position, making a decision to switch to the other one of the first and second interpolation modes, and starting a transition phase in response to said decision; selecting the third interpolation mode at said output pixel position for computing output pixels at said output pixel position in successive output frames in said transition phase.