def quintic(x, n, offset=0):
# can't just convolve, need to set boundary conditions
xbc = quintic_pad(x)
xup = filtering.upsample(xbc, n)
h = quintic_filter(n, offset)
y = filtering.filter(h, xup)
# delay of filter is 3*n - 1, so with b.c. padding of 2*n, start at 5*n - 1
start = 5 * n - 1
# stop at the last 'valid' (no implicit zero padding in conv) value
stop = -len(h) + 1
return y[start:stop]
