Chroma Key - Blackmagicdesign ATEM Mini Installation And Operation Manual

Setting up a Luma/Linear Key on the Downstream Keyer using
ATEM 1 M/E Advanced Panel
1 Press the 'DSK 1 tie' button to enable the downstream keyer on the preview
output. This automatically selects the downstream key menu on the system control
LCD, but you can also press the 'keyers' button and press the right arrow to enter
the menu directly.
2 Press the 'DSK 1' or 'DSK 2' soft button to select which downstream keyer you wish
to use. You don't have to select the key type as the downstream keyer is always
a luma key.
3 Use the control knobs under the LCD menu to select the fill source and key
source. You can also use the corresponding source select buttons to select the fill
and key source.
4 Once you have chosen the fill source and key source, use the 'left' and 'right'
control buttons to scroll through additional menu screens containing key
parameters such as mask, gain, clip, pre multiplied key settings, and more.

Chroma Key

Chroma key is commonly used for weather broadcasts, where the meteorologist appears to be
standing in front of a large map. In the studio the presenter is actually standing in front of a blue
or green background. In a chroma key two images are combined using a special technique and
a color from one image is removed, revealing another image behind it. This technique is also
referred to as color keying, color-separation overlay, green screen, or blue screen.
A very common use for chroma keys for backgrounds is computer generated graphics.
It's simple to connect an external computer to your ATEM switcher using the HDMI output of the
computer or a video card such as the Blackmagic Design DeckLink or Intensity range and then
play back video clips to your ATEM switcher. If you render a green background on your
animations, you can then key this green to create fast and clean animations of any length.
Keying is easy as the green is computer generated so it's a very flat color that's easy to key.
Combining a background with a fill and chroma key mask
Background
A full screen image; in the case of a chroma key it is often a weather map.
Fill
The image you plan to display on top of your background video. In the case of a chroma key,
this is video of the meteorologist in front of the green screen.
Key/Cut
In the case of a chroma key the key/cut signal is generated from the fill signal.
Keying using ATEM Mini 94