johnmeyer is right, but @GMJCZP I understand what you wanna do as well, so let's try to clarify it a bit more xD
So... let's start from the beginning:
a video can be progressive, telecined or interlaced;
in case of NTSC videos, if they are interlaced they have been made in 29.970 and then they have been interlaced 60i; if they are telecined, instead, it means that they have been "converted" from 23.976 to 29.970 by duplicating frames in a constant pattern and then interlaced to 60i.
So far, so good (and we all know these things).
Now... what johnmeyer basically said is that anime are not as movies, which means that, since drawing several scenes and animate them costs a lot of money,
they try to avoid to animate characters as much as they can, which leads to several repeated frames (by purpose).
So you are gonna have repeated frames anyway, because they are intentional.
That said, let's assume we have a 23.976 fps progress video which has been converted to 29.970 progress and then interlaced to 60i (telecine).
If you run a decimating filter through it, it will be "confused" by all the repeated frames it will find, which will be the ones duplicated during production/animation (to save money) plus the ones created during the telecine process.
That's what he was trying to tell you.
On the other hand, I got your point, because you have a telecined source which has been wrongly deinterlaced instead of applying an IVTC.
Anyway, I can tell you that on telecined sources, this would probably get the job done and return you an acceptable 23.976 fps progressive file:
tfm(mode=1,pp=5,slow=2,micmatching=2,clip2=tdeint(mode=2,type=3))
tdecimate()
Anyway, since you have a deinterlaced file to be used as source, I suggest you to get the original NTSC telecined file and then use what I wrote above.
Besides, you said that there are "artifacts" in your output, right?
But... decimating filters don't do anything like blending or interpolating etc... they just "decimate" (remove frames) (note: not entirely true, there are filters that blend two frames together, like when interlaced NTSC DVD are converted to PAL, but that's NOT the case), so... what do you exactly mean by "artifacts"?
I mean, in the very worse case, they won't get the right telecine pattern because they are confused by the duplicated frames and they will simply remove the wrong frames, making your video looks even less smooth than before, but without any artifacts of course, so what do you exactly mean by that?
Don't get me wrong, I'm just trying to understand.
p.s @johnmeyer... if I got you wrong, feel free to tell me.
