Some TVs and receivers have a night mode that does what you want. It's basically a compressor that cuts off the high peaks. I've always been told that the ads

Some TVs and receivers have a night mode that does what you want. It's basically a compressor that cuts off the high peaks. I've always been told that the ads are not really louder, that's another compression technique at work. There's no dynamic range and everything is at the top of the volume range. ( I think it amounts to the same thing )