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python.exe crash if opencv tries to access busy webcam

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  python.exe crash if opencv tries to access busy webcam ifelsetrue@gmail.com - 2013-07-03 06:25 -0700
    Re: python.exe crash if opencv tries to access busy webcam Tim Golden <mail@timgolden.me.uk> - 2013-07-03 14:38 +0100

#49731 — python.exe crash if opencv tries to access busy webcam

Hello,


I have a while loop taking images every 5 minutes from webcam. Unfortunately, if the camera is busy, python.exe crashes and there is no exception to catch. Is there a way to check if camera is busy to avoid the crash?


Thanks!

from cv2 import *

while True:
    time.sleep(4)
    cam = VideoCapture(0)
    s, img = cam.read()
    if s:    # frame captured without any errors
        namedWindow("cam-test",CV_WINDOW_AUTOSIZE)
        imshow("cam-test",img)
        waitKey(0)
        destroyWindow("cam-test")
        imwrite("filename.jpg",img) #save image

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#49733

On 03/07/2013 14:25, ifelsetrue@gmail.com wrote:
> Hello,
> 
> 
> I have a while loop taking images every 5 minutes from webcam.
> Unfortunately, if the camera is busy, python.exe crashes and there is
> no exception to catch. Is there a way to check if camera is busy to
> avoid the crash?

If python.exe crashes -- ie exits completely without a traceback, then
it's most likely a flaw in the extension module which is capturing the
image. If that's the case, there's nothing you can do in Python code to
prevent it; you need to work with the project maintainers to fix that.

If you're getting a traceback but the console window is then closing too
fast for you to see it, then try running the code from an open console
window rather than double-clicking on it. (You don't say how you're
kicking the code off so I'm offering this just in case)

TJG

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