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Author Marc FD
Version v0.95
Download asharp
Category Sharpeners
License GPLv2
Discussion Doom9 Thread



asharp is an adaptive sharpening filter; basically a very common unsharp mask with 3 simple ideas:

  • Adaptive thresholding to avoid noise enhancement.
  • Block adaptive sharpening to avoid DCT block edges enhancement.
  • Block based adaptive thresholding to avoid DCT block edges enhancement.

Like most AviSynth sharpeners, asharp only processes the luma channel, the chroma channels are simply copied from the input clip (chroma sharpening seems to only introduce artifacts).


Syntax and Parameters

asharp (clip, float "T", float "D", float "B", bool "hqbf")

clip   =
Input clip.

float  T = 2
Unsharp masking threshold. Range is from 0 to 32. 0 will do nothing, 1 is like 32 with ffdshow/VDub unsharp mask filter, it'll enhance contrast 1x.

float  D = 4
Adaptive sharpening strength. Range is from 0 to 16.
  • Set to 0 to disable.
  • If D>0, adaptive thresholding is enabled. The threshold is adapted for each pixel (bigger for edges). If adaptive sharpening is enabled, T acts like a maximum.

float  B = -1
Block adaptive sharpening. The range is from 0 to 4.
  • Set to a negative value to disable (default).
  • If B>=0, block adaptive sharpening is enabled. It acts very simply, by lowering the threshold around DCT-blocks edges. If you use it, avoid any non mod8 cropping before asharp.
  • It works only with adaptive sharpening, when D>0.

bool  hqbf = false
High quality block filtering (aka block based adaptive thresholding). Set to true to enable.


asharp with default settings (adaptive sharpening):

asharp(T=2, D=4, B=-1, hqbf=false)

Simple unsharp masking with a strength of 2x (adaptive sharpening disabled):

asharp(T=2, D=0)


Version      Date(D/M/Y)      Changes
v0.95 27/11/2002 - fixed some bugs - added mmx compatibility - first GPL source release

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