Vapoursynth "Only apply to" frame range issue

[Selur]

I'll add a tool-tip with:

Each line in the text file or in the mappings string must have one of the following forms:
'a z'
Replaces frame a in the base clip with frame z from the filtered clip.
'[a b] z'
Replaces all frames in the range [a b] of the base clip with frame z from the filtered clip.
'[a b] [y z]'
Replaces all frames in the range [a b] in the base clip with frames in the range [y z] from the filtered clip. If the input and output ranges do not have equal sizes, frames will be duplicated or dropped evenly from [y z] to match the size of [a b]. If y > z, the order of the output frames is reversed.

as description, that should help.

Cu Selur