SangnomAA() with chroma optimization

function sangnomaa(clip a, int "ss") {
    cr=a
    a.converttoy8
    ss=default(ss,2)
    spline36resize(a.width,a.height*ss)
    sangnom2.spline36resize(a.width*ss,a.height ).fTurnRight().sangnom2.fTurnLeft().spline36resize(a.width,a.height )
    converttoyv12
    return mergechroma(cr)
}