Is there a program that will regulate the volume of TV input through a tuner card?

[MrBond]

I don't have a TV in my bedroom, so I use my PC with a WinTV card. The problem is, the volume level of commercials is higher then the volume level of TV shows. Normally, it's not a problem, but at night I'd like it to be consistant. If I have it loud enough that I can hear it out of the speaker by my bed when the show's are on, the TV commecials are loud enough that I'm worried about waking my roomates. Many TV's have "SmartSound" that keeps the volume level at the same place, regardless of what's on, but is there something I can use for my pc that will do the same thing?