Graphic Cards w/ Video Input and OpenGL Support

Marco Bertini asks: "I'd like to know which graphics card with video input (S-Video or coaxial) are supported by Linux, and if there's any library to handle video input. My problem is to acquire two video inputs from cameras at the same time. At present I'm doing it on SGI O2, using the Digital Media libraries for video input, and OpenGL extensions for edge detection using it's h/w boost. Is it possible to switch to Linux to do it ? It seems that for example ELSA GLoria Synergy offers OpenGL h/w accelaration supported by Microlink Extreme 3D, but I'd like to hear about live experiences, and other options. "