Overview of, Compositing using the chroma keyer filter – Apple Final Cut Express HD User Manual
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Part IX
Overview of Compositing Using the Chroma Keyer Filter
While you can use one of several different filters for keying, you often use more than
one filter, depending on the qualities of the video clip. In general, the process of
compositing two shots together by keying consists of seven main steps, using several
different types of filters. For more details, see “
Example: Using the Chroma Keyer Filter
Step 1:
For best quality, start with the Color Smoothing filter
Apply the Color Smoothing filter to the clip that you want to key the background out
of. This filter improves the quality of chroma keys and reduces the diagonal “stair-step”
look that occurs in video clips with areas of high-contrast color.
Use 4:1:1 Color Smoothing with NTSC or PAL DV-25 video sources. (The exception is
PAL mini-DV/DVCAM, which uses 4:2:0 color sampling.) Use 4:2:2 Color Smoothing for
DVCPRO50 and 8- and 10-bit uncompressed video.
As you add additional keying filters, make sure that the Color Smoothing filter remains
the first one listed in the video section of the Filters tab.
Step 2:
Apply the Chroma Keyer filter
Now you can apply the Chroma Keyer filter to the clip. Choose a color or level of
brightness to key on, and then make adjustments to select the range of color or
brightness that most effectively keys out the background, without eliminating the
details of your foreground subject, such as hair, fingers, or the edges of clothing. You
can also use the Thin/Spread slider to adjust the fringing that appears around your
foreground subject, but don’t use it too aggressively.
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Tip: While the Chroma Keyer filter is the fastest and easiest to use, you may find that
the Blue and Green Screen filter, in conjunction with the Matte Choker filter, can
perform a closer key on certain clips that have more subtle detail around the edges of
the foreground subject. For more information on the controls of the Blue and Green
Screen filter, see “