resizeroo.py

import vapoursynth as vs
import math
core = vs.get_core()

def nice_round(x, base=2):
    return base * round(x / base)

def resizeroo(clip, max_width, max_height, func):
    ratio = min(max_width / clip.width, max_height / clip.height)
    clip = func(clip, nice_round(clip.width * ratio), nice_round(clip.height * ratio))
    border_left = (max_width - clip.width) / 2
    border_top = (max_height - clip.height) / 2
    if border_left % 2 == 1:
        border_left += 1
    if border_top % 2 == 1:
        border_top += 1
    border_right = border_left
    border_bottom = border_top
    if clip.width + border_left + border_right > max_width:
        border_left -= 2
    if clip.height + border_top + border_bottom > max_height:
        border_bottom -= 2
    clip = core.std.AddBorders(clip, border_left, border_right, border_top, border_bottom)
    return clip

# thing = resizeroo(thing, 1920, 1080, core.resize.Spline36)