Chromakeying – NewTek TriCaster 855 User Manual
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Hint: Clicking Configure for the video monitor in the Scopes tab likewise opens the Input
Configuration panel for the corresponding Switcher row source. For Program and Preview
selections, note that the controls only affect the Background source (not any active DSK
channels). Also, Configure controls are not provided when the Program or Preview source is a
Virtual Input.
11.1 CHROMAKEYING
The method by which part of the image is defined as transparent is generically referred to as
chromakeying, for its dependence on the color values (chrominance) of the video stream.
Note: Internally, LiveMatte actually goes well beyond simple chromakeying techniques to provide
its great realtime results - but we’ll stick with fundamentals for our discussion here.
Chromakeying has become an essential tool in video and film production. Typically, foreground
footage is shot in front of a blue or green screen, and then that background color – the key color
– is treated as transparent, allowing another image to be inserted.
Figure 186
For example, when you see a television meteorologist in front of a weather map, that person is
almost certainly posed in front of a green screen. The background is ‘keyed out’ and replaced by
computer generated imagery.