Check page 22 of the user manual.
Changing the Screen Aspect Ratio
The TV can display images in five different modes: Normal, Stretch,
Panoramic, Wide, and Zoom. Each mode displays the picture
differently.
To change the screen aspect ratio:
1. Press the WIDE button on the
remote.
2. Use the Arrow buttons to
highlight the aspect ratio you
wish to view and press OK.
• Normal preserves the content’s
original aspect ratio. Since the
4:3 aspect ratio is not large
enough to fill the TV’s screen,
black bars are added to the left
and right of the display image.
• Stretch expands the display image to fill the screen.
Images may appear wider than intended. If you are
watching widescreen (1.85:1 or 2.35:1) content, black
bars will still appear on the top and bottom of the display
image. This option is only available when the TV is
displaying a 720p/1080i source.
• Panoramic expands the display image to fill the screen.
Images may appear wider than intended. If you are
watching widescreen (1.85:1 or 2.35:1) content, black
bars will still appear on the top and bottom of the display
image. This option is only available when the TV is
displaying a 480i/480p source.
• Wide stretches a 4:3 aspect ratio picture to the edges
of the screen. Since the picture is being stretched, the
display image may appear distorted. If the program
is already formatted for widescreen viewing (1.85:1 or
2.35:1), then black bars will appear on the top and
bottom of the display image.
• Zoom expands images with black bars to fit the screen
http://cdn.vizio.com/documents/downloads/hdtv/E320iB1/UM_E320iB1.pdf