python video capture loop

I've written a simple script to continuously capture snapshots from my webcam. My only issue is the videocapture module doesn't always grab an image which in turn crashes the program. I think I could solve this by using an infinite loop but I'm not real certain how to go about开发者_运维知识库 it. Here's the script:

from VideoCapture import Device
import datetime
def capt():
  a = datetime.datetime.now().strftime("%Y%m%dT%H%M%S%ms")

  b = str(a)
  cam = Device(devnum=0)
  cam.setResolution(1280, 960)

  cam.saveSnapshot('%s.png' % (b))

for i in range(1, 100000):
  capt()

Try to use cam.getImage instead of cam.saveSnapshot. cam.getImage returns PIL image, thus you are able to determine whether any frame has been actually grabbed or not. The folloing code hasnt been tested:

from VideoCapture import Device
import datetime
def capt():
  a = datetime.datetime.now().strftime("%Y%m%dT%H%M%S%ms")

  b = str(a)
  cam = Device(devnum=0)
  cam.setResolution(1280, 960)

  return cam.getImage(), b

while True:
  im, b = capt()
  if im:
    break
im.save('%s.png' % (b), 'JPEG')