# Quick question on TIVTC's Tdecimate

1. EDIT: Talking about Avisynth plugin.

Sorry if my question seems weird, because I think people don't normally do this.

but if I want to remove half of the frames using Tdecimate, is there a difference between

cycleR= 1, cycle =2

and

cycleR=4, cycle=8

Will they function the same?
2. They may not act the same. TDecimate() preferentially removes duplicate frames. In a sequence like "0 0 1 1 2 2 3 3" you will get the same result, "0 1 2 3". But with a sequence like "0 0 0 0 0 1 2 3 " the former will give you "0 0 1 3" or "0 0 0 2", the latter "0 1 2 3". Ie, the former case it looks at groups of 2 frames and then removes one (hopefully a duplicate, but if there is no duplicate a unique frame will be removed. The latter looks at groups of 8 frames and removes the 4 duplicates.
3. Originally Posted by jagabo
They may not act the same. TDecimate() preferentially removes duplicate frames. In a sequence like "0 0 1 1 2 2 3 3" you will get the same result, "0 1 2 3". But with a sequence like "0 0 0 0 0 1 2 3 " the former will give you "0 0 1 3" or "0 0 0 2", the latter "0 1 2 3". Ie, the former case it looks at groups of 2 frames and then removes one (hopefully a duplicate, but if there is no duplicate a unique frame will be removed. The latter looks at groups of 8 frames and removes the 4 duplicates.
Alright, thank you
4. If you want to remove half the frames, TDecimate is the wrong tool. Use Selecteven() or Selectodd(). Either one will do. They are both specialized versions of the more general SelectEvery() function.
5. TDecimate has modes without a "cycle" length as such.

TDecimate(mode=7, rate=24.0/1.001) will output 23.976fps. It may or may not work better than the standard modes, depending on your source. Mode=2 can be used for 2 pass duplicate removal.

If you just want to remove every second frame, as previously mentioned..... Selecteven() or Selectodd()

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