Need Warpsharp for low luma areas only

[digitize]

A filter idea from a friend, who asked me to post. A warpsharp filter that only works on low luma values, which should warp the light surrounding values into the black.

[Si]

warp the light surrounding values into the black

What's that in English then :)

e.g what does "your friend" mean and why do they want to do it?

regards
Simon

[mf]

I was too lame to post myself :D. An effect I noticed from warp sharp is that it makes cartoon lines thinner, but at high strengths normal picture is affected too. So something that only works on the dark (= low luma) lines would be great.

[esby]

That could be done by linking warpsharp to a mask?
two options:
or we links processing with a mask.
or we do some overlay of the original frame according to the mask.

In this last case, we'll just need a filter that creates a mask
according to a luminance threshold,
another that will do the overlay stuff
something like

clip = assembly( clip, clip.warpshard, clip.CreateMaskFromLuminance(threshold) )


esby

PS : i dont think if the assembly filter exists, but i think it should be possible, since the mask is a frame too, and this can/could be applied to any type of filtering.

PS2: the inconvenient of this method, is that you may see difference between the masked part and the non masked part if the filter is altering too much the linking area...

[mf]

Well actually "low luma areas" would be a wrong description, since it should only WARP low luma areas. As in: if I have a blurred line running over a white surface, it should warp (make thinner) only the blurred line. Anyway, a more detailed description of why I'd need this is in this thread, at the bottom. (http://forum.doom9.org/showthread.php?s=&threadid=47475) It's actually for use with line darkening.