User guide

Shot Editor
Shot Editor Chroma Key
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Wirecast User Guide | 154809
Selecting a Key Color
To get the best key possible, select the key color using the mouse. To do this check the
Pick key color with mouse checkbox. Use the mouse to click a point on the image in the
preview area. As you do this watch the preview change in level of transparency,
displaying the gray/white checkerboard pattern on the affected regions. Usually,
clicking near the corners of the media provides the best key, but sometimes clicking
near the main subject in the image is best.
Key Threshold
Once you have the best key by picking the color, you can adjust the key threshold to
drop out the background as completely as possible. The Key Threshold parameter
enables Wirecast to determine how close the color in the video is to the key color.
Adjust the key threshold (0 to 100) by using the slider.
Black Clip
Sometimes, dark areas are keyed out, when they should not be, due to how digital
cameras function. The Black Clip parameter controls how close the keying is toward
black. For example, if the host has black hair, you need to increase this value slightly so
that the keying effect is not seen in his hair. Adjust the Black Clip (0 to 100) by using the
slider.
White Clip
Likewise, white areas are also sometimes keyed out when they should not be. The
White Clip parameter controls how close the keying is toward white. For example, if the
host has a white shirt on, you need to increase this value slightly so that the keying
effect is not seen in his shirt. Adjust the White Clip (0 to 100) by using the slider.
Getting a Good Key
Probably the most important part of getting a good key is getting good source
material. Poor source material generates poor keys; no algorithm can make up for this.
Lighting
Assuming you have a reasonably good camera, the most important part of getting a
good key is good lighting. Invest in good lights and learn how to set them up properly.
Here are some basics:
• The background screen (green or blue) needs to be independently lit from other
items in the shot.
• Light the background screen evenly, with no shadows. The more evenly lit, the bet-
ter the keying.