Sometimes I see HDTV's on display at the store showing analog video which appears to be "stretched" to fit the screen. How can I tell if a TV has a feature to *not* stretch analog input (ie. show analog video at its regular aspect ratio with black void on the sides)? I'd like to buy a HDTV for DVDs and Off-Air HDTV but I don't want to watch my analog Off-Air channels in a "stretched" form. TIA!