Widescreen televisions provide several modes for displaying video from 4:3 (standard aspect ratio) sources.
These modes may be selected manually from a remote control, or automatically if an Active Format Description is available.
Normal mode frames the 4:3 video to the 16:9 picture area by displaying it in its original aspect ratio, with vertical gray or black bars on both sides of the screen.
The disadvantage of this method is the fact that the image is small by virtue of not using the entire width of the screen.
This allows normal aspect ratio video to be displayed across the entire width of the screen, with minimal cropping, and with much less of the unpleasing visual stretching effect of Full mode.