Grass Valley Kayenne v.3.0 - Manual (Page 45)

KAYENNE — User Manual45
Keying
Opacity
The opacity of a key can be adjusted. When opacity is reduced below 100%
some background video is allowed to show through areas where it is nor-
mally excluded. Key opacity is an adjustment to the overall intensity of the
key, and is separate from Clip and Gain controls. Note that a common
mistake is to set opacity to zero and forget that adjustment was made,
which can cause confusion later when that key is selected but not visible.
Key Positioning
Key positioning allows slight adjustment of the horizontal position of the
key cut signal relative to the key fill signal. This is useful if the timing of the
two signals at the switcher inputs are not matched properly. This is gener-
ally only a problem if the cut or fill follow analog paths from source to
switcher or if the source has video/key timing adjustments which have
been set to compensate for other delays within the facility.
Key Size
Key size allows the key cut signal to be narrowed slightly. This can greatly
enhance self keys and chroma keys that have been reshaped.
Coring
Coring helps reduce video noise in Chroma keys. Coring is used when a
key fill signal has noise in areas that are supposed to be transparent. When
noise exists in these areas it can appear in the background portion of the
keyed composite. Coring replaces the noisy black areas outside the shaped
fill with clean black before it is summed, eliminating the noise.
Show Key
Although the key control signal is not directly visible in the final video
output, this signal can be previewed as a black and white image using the
Show Key function. White areas of a show key indicate areas of complete
opacity, black indicate complete transparency, and gray areas indicate
translucent areas of the key. The whiter the show key signal, the more
opaque the key will be. This key preview signal reflects all the adjustments
that have been made to the key control signal.
Linear Key
A linear key typically uses separate key cut and key fill input signals that
are intended to be used for linear keying. The key cut and key fill are
usually anti-aliased (soft edged) shaped signals created by a character gen-
erator or graphics system. There may also be translucent areas intended to