[feature request] webcam support

Please

I am impatient to get something as "-device usb-webcam" to share dynamically the webcam between host and guest.

I use

-device usb-host,vendorid=0x046d,productid=0x081b

But in this case the webcam belongs to the guest and the host can't use the webcam.

I want a dynamical sharing like the mouse sharing for example.

Thanks