#
minvar

Author V. C. Mohan
Date 30 Dec 2016
EMail: mohanvc

This is an adaptive local noise reduction filter. It uses global variance of the noise, local mean and local variance in a moving grid of specified size. It tries to preserve edges as closely as possible.

works in YUY2, Planar and, RGB color spaces and for all bit depths supported by avisynth+. This is thread safe : MT_NICE_FILTER.

The window for computing global variance be located in an area with least image grey level (luma) variations, and as large as possible (10,000+ pixels) so that noise statistics are correctly estimated. Note that for this window, coordinates must be specified as default values are not provided

The process tries to retain the sharpness of the image, though some blurring may be unavoidable. The process may be repeated number of times to get desired result. However results depend on window selected.

Details of parameters
Description | Name | Type | Limits | Default
Input clip |  | clip |  | none
frame number in which specified window is located | sf | integer | within clip | 0
Number of pixels along x axis in moving grid | xgrid | integer | 3 to 9 | 5
Number of pixels along y axis in moving grid | ygrid | integer | 3 to 9 | xgrid
window left x computing global variance | lx | integer | within clip, less than rx | none. Must be specified
window top y for computing global variance | ty | integer | within clip, less than by | none. Must be specified
window width for computing global variance | wd | integer | lx + wd be within frame | none. Must be specified
window height for computing global variance | ht | integer | ty + ht be within frame | none. Must be specified
Whether U and V of YUY2 and YUV formats to be processed | uv | boolean | true for uv process, false for not process | true
Whether A value of RGB formats to be processed | a | boolean | true yes, false no | false
Whether variance values are to be displayed as an error message | show | boolean | true yes, false no | false

Usage examples
minvar()
minvar(sf = 35,lx=220,wd=245,ty=322,ht=150, uv = true)

To my index page down loadmodPlus plugin To Avisynth