How to make USB camera work with OpenCV?

user_210342 0
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I copied code from https://stackoverflow.com/a/34588758/210342 and used with default (built-in) camera, it worked. Then I attached USB camera, tested it with VLC and changed the code to open camera 1:

cam = cv2.VideoCapture(1)

I check whether the camera is open cam.isOpened() -- it is -- but the camera is not enabled (its hardware indicator, LED, is off) and indeed all I see on the screen is black frame.

Is there some extra special code to add in order to enable USB camera?

windows-7-x64 opencv webcam python
5 Answers

You can also refer this link here

https://devtalk.nvidia.com/default/topic/1027250/how-to-use-usb-webcam-in-jetson-tx2-with-python-and-opencv-/

Here he changes the line below to 

cap = cv2.VideoCapture("/dev/video1") # check this

Before plugging in the camera, go to your terminal home

  1. Type cd /dev
  2. Type ls video and then press tab, if you find only result as video0, that means only webcam is present.
  3. Now repeat 1 to 2 with USB webcam plugged in. You should find video1 or video2 when you repeat the steps.
user_17533560

Are you sure the usb camera is camera 1, i've done this before and had to use cv2.VideoCapture(0)

user_37125310

I ran into the same problem, turns out sometimes the webcam can take both slots 0 and 1. So cam = cv2.VideoCapture(2) worked for me. This was found using the cd /dev-method above.

user_82747840
user_44519440

I do not know why but on my laptop (Acer Aspire 3) the usb webcam works with python opencv only if I plug it in the right side usb of my laptop and NOT if I plug it in the left side usb. So try plugging the webcam on all the usb ports you have. (I also had to use cam = cv2.VideoCapture(2) as @Slayahh suggested.

user_31054850
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