Kramer Electronics VP-770 - Manual (Page 39)

34 VP-770 - The OSD Menu
BEST FIT – This setting re-sizes the video or
graphics input signal to “best fit” the output resolution
while maintaining the aspect ratio of the input signal.
For example, a composite video signal (4:3 aspect
ratio) will “best fit” to the top and bottom of a
widescreen output image, resulting in black pillars on
either side.
LETTERBOX – This setting compresses the top and
bottom edges of the input signal, but fills the width of
the screen. For example, to preserve a widescreen
film image on a 4:3 display.
6.7.2 Master Connection Settings
The Master Connection (HDMI, DGKat or PC) is usually set to the main output
display so that the optimal resolution for that display can be obtained. By setting
the output resolution to Native, the VP-770 is triggered to read the EDID of the
main display and change the output resolution value according to the native
resolution of the display.
Note that when the output resolution is set to Native:

If HDMI/DGKat is selected as the Master Connection, and a new display is
connected to the Master Connection output (hot plug), the VP-770
automatically reads the EDID of that display and updates the output
resolution accordingly

If it is not supported by the selected Master Connection, the system
searches for the best supported resolution. If the search fails (for example, if
the master connection is disconnected or EDID is unreadable), the
resolution will default to XGA