VP8 output with VideoWriter in python doesn't work

[Garret Raziel]

I made simple python program that uses VideoWriter and VP8 codec for output into webm format, but it doesn't create anything. If I try different format ("THEO" and *.ogv for example), it works. Try this simple python program:

import cv2
from numpy import *

a = zeros((768, 1024, 3), dtype=uint8)
b = ones((768, 1024, 3), dtype=uint8)
vw = cv2.VideoWriter("out.webm", cv2.cv.CV_FOURCC(*"VP80"), 24, (1024, 768), 1)

for x in xrange(256):
    vw.write(a)
    a = a + b

It finishes without error, but out.webm file doesn't exist.