Blackmagicdesign ATEM Installation And Operation Manual page 131

To set up a chroma key on the upstream keyer on an ATEM Television Studio Pro
model switcher:
1 The first step is to press the KEY 1 TIE button to enable the key on the preview output
so you can see the key during the setup stage.
Pressing the KEY 1 TIE button ties the key to the next transition so it will transition to air
when the next transition is performed.
2 In the LCD menu upstream key settings, set the key type setting to 'chroma'.
3 Return to the upstream key menu and scroll down to the fill source setting. Select the
image you want to key as the fill source.
4 Adjust the chroma key settings while watching the preview output to refine the key.
When you are happy with your settings for the chroma key, press the 'menu' button to
step back through the menu until you return to the master program output.
To set up a chroma key on the upstream keyer on the software control panel:
1 Expand the upstream key 1 M/E 1 palette and select chroma from the key types bar.
2 Select the fill source.
3 Adjust the key parameters to refine the key. For a description of chroma key
parameters, refer to the table below.
Chroma key parameters:
Fill Source
Hue
Gain
Y Suppress
Lift
Narrow Chroma
Key Range
Mask
Selects the source to be keyed over the background. For example, a video
source of a weather presenter standing in front of a green screen.
The hue adjustment selects the color that will be replaced. Rotate the settings
knob until the background keys through the desired color.
The gain adjustment determines how the colors around the selected hue are
keyed. Adjust the gain until the edges of the keyed region appear the way you
want them.
Adjust this setting until the black level of the chroma removed region
is correct.
Lift should normally be set to zero for a well set up chroma key scene. Lift
allows very low saturation values of the keyed color to be excluded from the
key. Colored light spilling onto a neutral colored object in the foreground will
sometimes cause small areas to key to the background source. Lift allows you
to fill these small holes in the key signal.
The acceptance angle of colors around the selected hue should generally be
as broad as possible to achieve natural looking chroma keys. Sometimes, if
some colors in the fill source are too close to the chroma key color, it may be
hard to exclude them from the key.
Enabling this setting uses a smaller acceptance angle around the chroma key
color. Choosing this setting temporarily, may help you center the hue
adjustment.
Allows you to mask out sections of the key. For example, if the green screen
does not fill the edges of the screen, you can use the mask setting to select
only the area of the screen you want to use.
To return the mask to the default settings, select 'reset mask' and press the
set button.
Keying using ATEM Switchers 131