Tektronix Grass Valley 3000 - Manual (Page 135)

3-27
Manipulating Video Images
The displayed picture has a front side and a back side, the same
way a U.S. dollar bill does. The side with George Washington on
it is the front, and the side with the pyramid/eagle is the back.
This is still true, even if you turn the bill around, twist it, or roll it
up; the front is always the side with George’s face on it. If you turn
the bill around 180 degrees, so that George is facing away from
you, then the front of the bill is facing away too, and the back of
the bill is visible. This is the difference between front/back and
near/far—front and back may be pointing in any direction, but
the “near” side is always the side that is visible, and the “far” side
is the side that is no visible.
When the DPM or switcher is initialized, the “Front” side of the
video is what is visible. The currently visible side is the Near Side.
If the video is rotated 180 degrees so that the front side is facing
away from our view, then the Back side is the Near side.
Remember that what is visible is always the Near side. Near
delegates the visible side (Front or Back). Far delegates the “not
currently visible” side (Back or Front)