I finished a new version of gsvideo (0.3.12), which adds the possibility of setting parameters for the input plugin in the GSCapture object. An useful application of this feature is to chose the input device in Linux as follows:
capture = new GSCapture(this, 320, 240, new String[] {"device"}, new String[] {"/dev/video0"});
Download from here.
Update (August 19th, 2012): In the latest release of GSVideo (1.0.0) you can just specify the name of the capture device as string argument without the need of using arrays or the additional “device” argument:
capture = new GSCapture(this, 320, 240, "/dev/video0");
codeanticode 