You_Too said:
Sorry if I get this wrong but doesn't all films on VHS, laserdisc or just any format have a cadence like 3:2? Or is it only on DVDs?
Because I know I've seen some IVTC plugins for avisynth which only needs to be set to 3:2 or something and it will remove all unnecessary frames.
As AntcuFaalb said, the pattern sometimes changes...especially on analog sources. In my limited experience, some of the AviSynth plugins will occasionally get confused on the first frame or two of a pattern change and dish-out a few blended frames.
Also, because of the additionally video noise on analog sources (VHS, LD, etc.), some plugins can fail to lock onto the 3:2 pattern because they read that noise as movement.