VarianSlim plugin for Avisynth 2.5 version, is free and the author does not give any guarentee for its operation. It may be downloaded and used at the users risk.
This is an adaptive local noise reduction filter that uses image value statistics in a moving grid while trying to preserve sharpness of image.
From a specified frame of the clip VarianSlim either auto selects a suitable window or uses user specified window to obtain noise parameterss, and their variation for each iteration till it meets the specified limit. Incase of RGB the green color and in case of Y-U-V formats, the Y plane is used for autoselection of window
Parameter ry, gu, by control whether a color is to be left out or processed, if so with what accent. A value of zero will leave out that color ( or luma or chroma). A value of one will use derived values. Any higher value may accentuate. Accentuation may soften the image so may be used cautiously.
Parameter limit is for stopping iteration if improvement is less than this %age over previous iteration results. This is determined separately for each color.
This plugin works in YUY2, YV12, RGB32 and RGB24 color spaces. Results of using rgb format may be slightly different to that of Y - U - V formats.
The window for deriving noise parameters, if autow is set to false, must be located in an area with least image grey level variations, so that noise statistics are correctly estimated. Note that this window coordinates must be specified as default values are not provided. If window is located in an improper part , then it can lead to heavy blurring. A minimum of 1024 pixels window be specified.
Due to use of grid a border of half value of grid around the frame will be left out unprocessed.
|frame number from which noise statistics to be determined||nf||integer||within clip||0|
|Number of pixels along x axis in moving grid||xgrid||integer||3 to 11||5|
|Number of pixels along y axis in moving grid||ygrid||integer||3 to 11||xgrid|
|Whether window to be selected automatically||autow||boolean||true for yes, false for use user specified window||true|
|minimum window size if autow is true||minw||integer||Between 1/128 and 1/16 of frame size||1/64 of frame size|
|limiting %age of improvement per iteration||limit||integer||Between 0 and 20||2|
|accent for red or Y||ry||integer||Between 1 to 500||1|
|accent for green or U||gu||integer||Between 1 to 500||1|
|accent for blue or V||bv||integer||Between 1 to 500||1|
|window left x at start frame for computing global variance||lx||integer||within clip, less than rx||none. Must be specified for autow being false|
|window top y at start frame for computing global variance||ty||integer||within clip, less than by||none. Must be specified for autow being false|
|window right x at start frame for computing global variance||rx||integer||within clip, more than lx||none. Must be specified for autow being false|
|window bottom y at start frame for computing global variance||by||integer||within clip, more than ty||none. Must be specified for autow being false|
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