Will a Standard Definition Video Play on a High Definition TV?

Aspect Ratio

• The "aspect ratio" -- the ratio of full screen height to full screen width --differs substantially when comparing HDTV to a standard television set. HDTV displays 16 pixels of width for each nine pixels of height, a ratio of 16-to-9. A standard television's 4-to-3 ratio (or 12-to-9 when re-arranged into ninths for the sake of accurate comparison) means that the HDTV picture is roughly 25 percent wider than the picture displayed on a standard TV. The default setting for high-definition television is to display the video at its original aspect ratio.

Standard Video on HDTV

• You can play standard 4-to-3 video on HDTV, but black bars will appear on the sides of the screen since the 4-to-3 format of the video won't provide a signal to fill the screen to its full width. The image, however, will not be distorted. If you want to fill the screen horizontally, you'll find that the HDTV tries to compensate for the change in width by compressing the height. This means actors who otherwise look like normal people will be compressed and circular objects will look like flattened ovals.

Letterbox Videos on HDTV

• Some 4-to-3 videos are "letterbox" videos, designed for the wide screen of a movie theater. These videos, when played on a standard 4-to-3 television, have black bars at the top and bottom of the screen. When letterbox 4-to-3 videos are played back on an HDTV, the characters and scenery will appear to be squeezed from side-to-side, as if trapped in a "video vice." You might notice this same effect if you try to play a video intended for HDTV on your standard television.

Change Settings When Needed

• The cure for most display problems with videos originally intended for standard television lies in changing the playback settings on your HDTV. If you see the "video vice" effect, where the characters are tall and skinnier than they should be, try changing the settings to the 16-to-9 widescreen setting; the bars above and below the picture will disappear and the video will display as intended. If you see black bars on the side of the picture but it is otherwise undistorted, sit back, relax and watch the show.