I bought a usb TV tuner/s-video/rca input device for my laptop, so that I can get video from DV video cameras and any other DV source straight into Gephex. Installation in Linux wasn't too hard:
First get usbvision:
cvs -z3 -d:pserver:email@example.com:/cvsroot/usbvision co -P usbvision
make; sudo make install
Tv time doesn't work, but zapping does:
"Your capture card driver, USBVision USB Video, is not providing
enough buffers for tvtime to process the video."
Gephex doesn't know how to change the channels or settings, so the trick is to change things in zapping and then quit and the settings will persist in gephex.