MakeFullDiff
============
.. function:: MakeFullDiff(vnode clipa, vnode clipb)
:module: std
Calculates the difference between *clipa* and *clipb* and outputs a clip with a one higher bitdepth to avoid the clamping or wraparound issues
that would otherwise happen with filters like *MakeDiff* when forming a difference.
This function is usually used together with *MergeFullDiff*, which can be used to add back the difference.
Unsharp mask::
blur_clip = core.std.Convolution(clip, matrix=[1, 2, 1, 2, 4, 2, 1, 2, 1])
diff_clip = core.std.MakeFullDiff(clip, blur_clip)
sharpened_clip = core.std.MergeFullDiff(clip, diff_clip)