import vapoursynth as vs
from vapoursynth import core
video = core.std.BlankClip(width = 1920,
height = 1080,
format = vs.RGB24,
length = 100,
fpsnum = 60,
fpsden = 1,
color = [0, 255, 0])
video2 = core.std.BlankClip(width = 1280,
height = 720,
format = vs.GRAY8,
length = 100,
fpsnum = 30,
fpsden = 1,
color = [127])
core.std.Splice([video, video2], mismatch = True).set_output()