Contrasharpener (VS)

def csharpmod(flt, src, strength=1, prefilter=0, darkened_merge=1, brightened_merge=1, darkening_limit=None, brightening_limit=None):

    pre = flt
    if prefilter >= 0:
        pre = haf.MinBlur(pre, rad=prefilter)

    if 1 < strength < 2:
        blur = pre.std.Convolution([1]*9)
    else:
        blur = pre.rgvs.RemoveGrain(11)
        for x in range(strength-1):
            blur = blur.std.Convolution([1]*9)

    diff = core.std.MakeDiff(pre, blur)

    if darkened_merge < 1:
        if darkened_merge <= 0:
            darkening_limit = 0
        else:
            diff = core.std.Expr(diff, 'x 32768 < x {} * {} + x ?'.format(darkened_merge, 32768 * (1.0 - darkened_merge)))

    if brightened_merge < 1:
        if brightened_merge <= 0:
            brightening_limit = 0
        else:
            diff = core.std.Expr(diff, 'x 32768 > x {} * {} + x ?'.format(brightened_merge, 32768 * (1.0 - brightened_merge)))

    clamp_expr = ' x '

    if darkening_limit is not None:
        clamp_expr += ' {} max '.format(32768 - round(darkening_limit * 256))

    if brightening_limit is not None:
        clamp_expr += ' {} min '.format(32768 + round(brightening_limit * 256))

    if darkening_limit is not None or brightening_limit is not None:
        diff = core.std.Expr(diff, clamp_expr)

    sharp = core.std.MergeDiff(flt, diff)

    if isinstance(src, vs.VideoNode):
        clips = [sharp, flt, src]
        min_src, max_src = [' z '] * 2
    else:
        clips = [sharp, flt] + src
        abc= [' {} '.format(x) for x in 'zabcdefghijklmnopqrstuvw'][:len(src)]
        mi = [' min '] * ( len(src) - 1 )
        ma = [' max '] * ( len(src) - 1 )
        min_src = ''.join(abc + mi)
        max_src = ''.join(abc + ma)

    return core.std.Expr(clips, 'x y {} min max y {} max min'.format(min_src, max_src))