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vcm

## Variance

The call script is :-

## vcm.Variance(clip,int lx,int wd,int ty,int ht [,int fn = 0][,int uv = 0][,int xgrid = 5][,int ygrid = 5])

clip: input clip of constant format. Compat input not accepted.
lx: Left x coordinate of window
wd: width of window
ty: top y coordinate of window
ht: height of window
fn: frame number in which window is located.
uv: If set 0 u and v planes of YUV format not processed.
xgrid: grid size along width. Minimum 3. Maximum should not exceed half of frame width, but be reasonably small.
ygrid: grid size along height. Minimum 3. Maximum should not exceed half of frame height, but reasonably smaller.

From the specified representative window, the global Variance is determined. In a moving grid the local Variance is determined and the center of the grid point is modified in relation to these two Variances. The algorithm ensures that local edges are not destroyed. Repeated use of this function cleans image and may be used for very noisy clips. For RGB all 3 planes are processed. The window should be as large as possible but have near uniform luma for YUV or Gray formats or uniform color and intensity for RGB format