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NTSC XGA Off NTSC XGA XGA
NTSC XGA On XGA NTSC XGA
(XGA is 1024x768)
You will see that the Swap between foreground and background has no effect on
the output resolution as this is always set by the Lock source.
The Min/Max parameters are used to select what range of Y (luminance/grey-scale)
values are made transparent within the selected window/lock source. In order to
key out part of an image, start with the max value and increase it until the required
lighter parts within the window/lock source disappear. Then adjust the min level to
bring back any darker parts of the image.
The Y Key softness option removes noise from the keyed image, generally at the
edges. Adjust as required to make the edges of the key as sharp or as soft as
desired. The noise is where the analog to digital process (A/D conversion) may not
sample a 50% brightness as being exactly 50% i.e. sometimes 49% and
sometimes 51%. Increasing the softness value will broaden the range of keyed
colors so that the keying of images varies depending on how close a color is to the
keyed-out range.
The Y Key invert changes the keying characteristics with respect to what colors of
the foreground image you wish to ‘key out’.
Setting it to Off will cause the colour range that’s defined to be removed - remove
the desired colours. Setting it to On will cause the colour range that’s defined to be
kept - key out all other colours.
The descriptions above behave identically on the remaining U Key Invert & V Key
Invert component versions. However they are directed at the U/B-Y (blue) colour
component and V/R-Y (red) colour components respectively. Adjustment and
effects are the same as explained above for Y Key Invert (brightness/grey-scale).
Adjust keyers
Y Key min/max [ 0] [ 32]
Adjust keyers
Y Key softness [ 0]
Adjust keyers
Y Key invert [Off]
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