ViewSonic VS12400 manual Aspect Ratio, Only TV Mode supports the Background function

Aspect Ratio

Auto—automatically selects the best aspect ratio for the input source.

16:9—A wide-screen aspect ratio for video.

4:3

6WDQGDUG79VFUHHQSURSRUWLRQDO- ly four units wide for every three units high, no matter the size of the screen.

5

6

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Press WX key or +/- to switch image size: 16:9, 4:3, Full, Panorama, Crop, or Standard.

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Press WX key to turn on the optional blue background.

Only TV Mode supports the Background function.

Panorama

Non-linear stretch right and left.	7	Press STNH\WRVHOHFW%DFNOLJKW
		Press WX key to increase or decrease the brightness of
		the backlight.

Crop

Vertically expanded, linearly 13%.

ViewSonic 30 VT2230-NT