MakeDiff
========

.. function::   MakeDiff(vnode clipa, vnode clipb[, int[] planes])
   :module: std

   Calculates the difference between *clipa* and *clipb* and clamps the result.
   By default all *planes* are processed. This function is usually used together with *MergeDiff*, which can be used to add back the difference.

   Unsharp masking of luma::

      blur_clip = core.std.Convolution(clip, matrix=[1, 2, 1, 2, 4, 2, 1, 2, 1], planes=[0])
      diff_clip = core.std.MakeDiff(clip, blur_clip, planes=[0])
      sharpened_clip = core.std.MergeDiff(clip, diff_clip, planes=[0])