How to find Frustum parameters??

I am doing Camera Calibration, and have lot's of local cameras, and I need to render frustum, and it's viewing angle for each. I know that i can do that with intrinsic and extrinsic parameters. BUT HOW??

If my understanding is right, i need to find : nearD, farD, ratio, angle. But again, how??

p.s. I have intrinsic and extrinsic parameters, for each local camera.