However, since the mid-1950s, many theatrically-produced films have featured wider aspect ratios, including 1.85 and 2.35.
Images displayed with black bars on the top and bottom are often referred to as “letterboxed.”
Aspect Ratios can vary from program to program.
Lifewire
Black Bars vs. Real HDTV programs fill the screen.
The TV screen is providing a surface upon which you view images.
Depending on the format, the entire picture might or might not fill the whole screen.
