VEAI already has several models for frame interpolation. In particular I love the arbitrary framerate interpolation (18fps super8 to 24fps BD, using 133%), showing that the interpolation can take place in an arbitrary time grid.
I would love to have a slider to adjust the start phase (0-100% with respect to the frame duration) for the interpolation.
Firstly, e.g. when using 200%, even frames are interpolated while odd frames remain the original ones.
Introducing a start phase (25%) will force every frame to be interpolated (to the cost of processing time). In some framerate conversion constellations the sequence of original to interpolated frames leads to some kind of pulsing. Introducing a start phase will probably reduce this effect.
Secondly, the start phase can be used to re-sync stereoscopic clips. With stereo clips the 3D effect gets very odd when the two cameras are out of sync, even by a fraction of a frame duration. So interpolation can restore clips that could not be used due to out of sync issues.
I’m sure, that only few users would use this slider, but since the interpolation grid can be arbitrary, this feature should not be a big deal and probably could easily be included in the GUI.
