HDTV – Why do those black bars still appear?

HDTV can trace its roots back to 1953. That is when The Robe starring Richard Burton, Jean Simmons, and Victor Mature was released to movie theaters. The Robe was the first wide screen movie, using a process called CinemaScope. Before then movies had been made with an aspect ratio of 4x3 (width by height) or a ratio of 1.33:1. Television also used this format. CinemaScope allowed for pictures twice the width of regular movies or a ratio of 2.66:1.

Along the way, Hollywood developed competing technologies to CinemaScope. These processes had names like Cinerama, Superscope, Techniscope, Todd A.O and VistaVision. They had varying degrees of wideness.

A problem arose with widescreen movies when, in the 1970s, movies were released to VHS and Betamax tapes for home viewing. TVs were not widescreen. There were two different solutions to this problem. Either release the tape in widescreen format or cut the picture to fit the TV screen. The widescreen release is also known as letterbox because the movie’s image only appears in the center of the screen with large black bars above and below the screen. However, since most TVs back then were 27-inch or less, the widescreen presentation created very small pictures.

The other method was to cut out parts of the picture so that what was left would fill the TV screen. The method used is often referred to as pan-and-scan. Formatting a widescreen movie to fit TV can result in almost half of the picture discarded. This can result in a dramatic shift in the way a viewer perceives a scene. Sometimes it can result in two people at either side of the image being almost out of frame. Generally, this is not too much of a problem because most of the action in a movie takes place center stage, but not all.

Along the way, TV screens grew in size. The invention of reasonably priced rear-screen projection models accelerated the shift to large screen TV. Eventually, industry and government decided to promote the new HDTV standard with a 16x9 (width by height) or a ratio of 1.78:1. This is a compromise. Any video shot in a wider aspect ratio will still need to be displayed in letterbox mode or cut to fit the screen.

A by-product of the new HDTV widescreen is that all standard definition TV is too small to fill the HDTV screen. And so nowadays, it is common to see black bars on the side of the screen rather than on the top and bottom. Some HD channels, particularly HD ESPN still use many standard definition videos. They fill out the sides of the screen with designs or banners so that the black bars are hidden.

Most HDTVs and some cable/satellite boxes have features that allow the viewer to adjust how the picture is displayed. One feature lets you zoom the picture to fit the screen. This is a variant on pan-and-scan. You lose some of the border of the picture so that the entire screen shows the picture. Another method stretches the picture to fill the screen causing distortion but you use the entire screen for which you paid.

I advise people to leave the picture alone. I do not like to zoom or stretch the video. Most new HDTVs are large screen and so the picture is large enough to comfortably view even if it does not fit the screen. However, there is an exception to my advice. Many standard definition broadcasts are now presented in letterbox form. This creates a very large effective border, on the sides, the top and bottom of the screen and makes the picture small. Zooming this type of picture results in a more satisfying viewing experience.