Grass Valley 1200 Operation Manual - Manual (Page 27)

2-9
Concepts You’ll Need to Know
Both background and foreground suppression include menu
controls for selecting the hue to be replaced and for adjusting the
luminance and chrominance levels in the areas of the picture
where suppression is applied.
Also included in the 1200 chroma keyer are a shadow processor
and a box mask. The shadow processor adjusts the amount of
shadow that chroma key foreground objects cast onto the
background, making the key look more natural. The box mask,
controlled from the Chroma Key Force Mask menu, can be sized
and positioned over a part of the key foreground or background
to prevent the key from occurring in that area.
Lastly, an Edge Control menu allows you to adjust the size (both
width and height) of the key edge in the black suppressed part of
the background. Adjusting for optimum key size ensures that
none of the black background suppression is visible along the key
edges.
Figure 2-4. Chroma Key Example
ForegroundVideo
Background Video
B L U E
Foreground Keyed Over Background