subprocess.call(['v4l2-ctl -i=N']) not works, why?

I’m trying to set inputs by calling “v4l2-ctl” command but fails.
By using subprocess.call, I can run ( -I ) but can not run ( -i=N ).

(1) WORKS
ret_v = subprocess.call([‘v4l2-ctl -I’], shell=True)

(2) NOT WORKS
ret_v = subprocess.call([‘v4l2-ctl -i=2’], shell=True)

The result is
VIDIOC_S_INPUT: failed: Device or resource busy

Please let me know why, or let me know other way to set it.

Thanks

Hi,
It looks to be a python issue. Suggest you go to https://www.python.org/community/forums/