How to stop guvcview displaying 2 entries for each USB video device ?

[kalpana]

When I try to select a device in the guvcview video controls tab, I see a menu where there are two identical entries for each physical device. Apparently selecting the first device of a given type results in video being displayed correctly, whereas selecting the second causes guvcview to hang.

I have a Logitech webcam and a USB Microscope. It is the microscope that causes the problems - only a single instance of the webcam is in the device menu until I plug in the microscope, then both the webcam and microscope entries appear doubly.

I have googled the issue and now believe that the second entry is a virtual device giving meta data about the second (this thread gives an explanation). v4l2-ctl shows both devices:

Code:

Code Select Expand

paul@clio:~$ v4l2-ctl --list-devices
UVC Camera (046d:0994) (usb-0000:00:14.0-13):
        /dev/video0
        /dev/video1

Digital microscope: Digital mic (usb-0000:00:14.0-5.1.1):
        /dev/video2
        /dev/video3
I have two questions:

Why do I only see the menu entries doubled up after I plug in the microscope ?
Is there any way to prevent guvcview doing this annoying behaviour ?


Many thanks.