Realtime Software MPEG2 Encoding Under Unix?

drix asks: "As part of a pet project I'm working on I need to encode MPEG2 video in realtime on Linux. I realize that there are many dedicated hardware boards being built explicitly for this purpose, but they are too expensive and I can't justify spending thousands of dollars for a hobby project. Currently several companies such as CinemaCraft and Ligos are advertising the ability to do realtime, DVD-quality MPEG2 encoding with heavily optimized software on a modestly powerful, PIII-700ish system, however all their products or SDKs are Windows based. I'm curious if anyone knows of similiar products designed to work on Linux. As an alternative, how much CPU would be needed to just 'brute-force' realtime, DVD-quality encoding using the standard (albeit sloooo) mpeg2encode program distributed by MPEG? Intel claims that a P3 1GHz can encode at 30fps, but apparently they turned down the quality, as this does not seem to be the experience of people on various newsgroups when trying to get DVD-like video."