how to limit frame using FSP property using python opencv

edit

i was trying to set FPS property to limit the frame per second... but, values are same and no frame are setting.

vid=cv.CaptureFromFile('out.mp4')
print cv.GetCaptureProperty(vid,cv.CV_CAP_PROP_FPS)
cv.SetCaptureProperty(vid,cv.CV_CAP_PROP_FPS,1)
print cv.GetCaptureProperty(vid,cv.CV_CAP_PROP_FPS)
fgbg = cv2.BackgroundSubtractorMOG()
#success,image=vid.read()
image=cv.QueryFrame(vid)
count=0
while image:
    #fgmask=fgbg.apply(image)
    #cv2.imwrite("frame%d.jpg" % count,fgmask)
    cv.SaveImage('pic'+str(count)+'.jpg', image)
    if cv.WaitKey(10)==27:
        break
    count+=1
    #success,image=vid.read()
    image=cv.QueryFrame(vid)