Actually this may not be as silly as it sounds, sure it doesnt suit telecide and fielddeinterlace but it would suit decimate. Decimate in mode 1 or 2 takes a fair bit of cpu time, a cache file for these could help a lot. For mode=1 all it needs is framex and the value it got for it (then it'd be simple enough to try other thresholds, or just the frame and blend/pass if you wanted to make it so thresholds couldnt be changed) For mode=2 the simplest would just be the frame#'s to drop, or list all the motion in each frame so the cycle can be changed without recaching. If I dont understand something of this let me know but as i see it it'd be quite useful in decimate.