[Linux-uvc-devel] Connecting multiple cameras

[David M. <dc...@MI...>]

Hi, I'm interested in connecting more than one camera at once,
specifically, a pair of Logitech Quickcam Pro 5000s.  I only have one at
the moment, but when I run it at full uncompressed resolution
(640x480x30fps YUV), it chooses an ISO endpoint with a packet size of
3060 bytes.  This is more than half of the available ISO bandwidth.
(cat /proc/bus/usb/devices claims it's 60% -- I expected more than half,
but not quite that much).  Obviously, this would prevent me from using
more than one camera.

By my calculation, 640x480x30fps YUV should take 2304 bytes minimum per
microframe.  So why can't the Quickcam choose its next smaller ISO
endpoint, which is 2688 bytes per microframe.  This would probably put
me at less than 50% of the ISO bandwidth?

Do you think this is a hardware limitation of the Quickcam, or is there
some driver involvement in this decision?

Thanks,

David