New answers tagged camera
Someone very helpfully pointed out on the Ubuntu subreddit that it could be down to a hotkey disabling it. He was absolutely right, I didn't know that hotkey done that so we can consider this one solved.
I had this problem with 14.04 until I installed "Cheese Webcam Booth" and then it worked fine.
It's just that the bandwidth of the USB ports is not enough to stream the data from the cameras. Try enabling them at a low resolution, or connect them in different ports.
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