I’m going to open two cameras and read one by one.
When opening two, there is not enough usb 3.1 bandwidth. (Problem is due to property)
At this time, since each camera reads one by one, is the bandwidth value the same as the camera that reads the bandwidth?
the cameras stream video to the host regardless.
your reading merely consumes from a host-side buffer. if you don’t read, the buffer grows, because the camera doesn’t care. if the buffer grows too large, the driver might complain and release the device.
USB UVC usually/always (?) uses “isochronous” USB transfers. the device always gets its bandwidth allocated by the controller. some other types of transfer get no bandwidth reservation and can share controller bandwidth more easily.
this goes for webcams. for industrial applications (“USB3 Vision” standard), there are ways to trigger single exposures in a camera, and it captures a picture precisely as commanded.
regardless, simply not reading on the host does not prevent images from being taken.