okay, a question from left field

Okay this question has nothing to do with recording our music but I figure if anyone can answer it, it is one of you geniuses. Does anyone know of a real-time compressor plug-in I can use with my Sound Blaster card that would automatically lower the audio on TV commercials and boost low level diologue as well. Also could be used to boost quiet talking and lower loud action scenes when watching DVDs. I use my computer for everything and I was just thinking it would be nice if..... Kevin