As mentioned in bug 811324, bug 802656 and bug 811757, the webrtc.org device capture code uses indexes to allocate devices. The problem is that the device lists are volatile, so if there's a delay between enumerating the list and allocating the device, the list order or number could change (USB plugin/remove, etc). This can cause the user to get a different device than they planned particularly if the plug/unplug a device while a doorhanger for access is visible. This is a small privacy risk (as user actions with hardware are involved). File upstream as bug 1118 (See URL) on Nov 15. Unlikely to be resolved anytime soon. We'll have to see if we can (partly) work around it by perhaps re-verifying that the devicename string matches the one we got before.