Brightness and contrast levels

I was wondering if the Apple TV and/or aTV Flash play with the brightness and contrast levels in videos. I have noticed that my videos appear a bit clearer and with a more preferable brightness and contrast level when played on my MacBook. Are there certain settings I should tinker with on my HDTV? My Apple TV is hooked up to the television via HDMI, but perhaps some quirky default settings are making my picture quality subpar.

 Any thoughts on the matter?

Some TVs will have different video settings for different inputs - I'd check to be sure the settings for the AppleTV input are the same as the settings for MacBook.