save rendering to video file

I would like to create a video file from an OpenGL/GLUT render. Does anyone know of a free/opensource Linux library to do this?

Thanks in advance!

I know ffmpeg ( can record content of your screen (I have never used this feature, but it should work.)
It contains tons of shared libraries with various video processing functionaliy, so it should be possible to capture window content from inside of your code.
some info:

Thanks for the reply kowal. I actually just found a couple programs to capture opengl animation. The one that I’m using is called glc and its very easy to use and install. It supports several exporting formats including mpeg4.

Other programs I found were yukon and fraps. fraps is for windows.