WarpDeRing

# WarpDeRing v1.0 by mirkosp
#
#   Uses aWarpSharp2's flattening to clean out ringing/smaller halos,
#   then runs some masks to preserve the edges and avoid the thinning.
#   This is nothing really new but it kind of just works, so eh.
#   Calling the filter more times in a row is probably more effective than toying with the parameters.
#   Only really tested out with a DVD, probably only works as intended on SD sources.
#   For HD, it might need some more mt_expand() in the owarp clip (I don't think, though).
#   Oh, and it's for newer and minor stuff, like downscaled HD sources released only on DVD and so on.
#   Don't expect this to work on Trigun. Or, well, I guess it could work, but... you know the deal.
#
# strength is the warpsharpening depth, so higher values nail more things
# tmax and tmin work out the hysteresis mask for the final masking pass
#
# Requirements:
#
#   awarpsharp2 http://forum.doom9.org/showthread.php?t=147285
#   mt_masktools https://github.com/tp7/masktools
#   nnedi3 http://web.missouri.edu/~kes25c/
#   fillmargins http://www.avisynth.nl/users/warpenterprises/
#

function warpdering(clip c, int "strength", int "tmax", int "tmin") {
strength = default(strength,6)
tmax = default(tmax,10)
tmin = default(tmin,7)
c
addborders(4,4,4,4)
fillmargins(4,4,4,4)
warp = awarp4(nnedi3_rpow2(rfactor=2).nnedi3_rpow2(rfactor=2),asobel(thresh=255).ablur(),depth=strength)
owarp = mt_merge(last,warp,tedgemask(valon=-1).mt_expand().mt_expand().mt_expand().mt_expand().mt_expand().blur(1),true,u=3,v=3)
mt_merge(owarp,last,mt_hysteresis(tedgemask(threshy=tmax),tedgemask(threshy=tmin)).blur(1),true,u=3,v=3)
crop(4,4,-4,-4)
}