Simple choker effect – Adobe After Effects User Manual
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Gray Level Softness
Specifies how soft to make the edges of the matte. At 0%, the matte edges contain only fully opaque and fully
transparent values. At 100%, the matte edges have a full range of gray values but may appear blurred.
3. Set stage-two controls (the next three properties) to choke the matte by the same amount as the amount by which you spread it in stage
one.
4. (Optional) Use the Iterations property to specify how many times After Effects repeats the spread-and-choke sequence. You may need to try
a few different settings so that the sequence is repeated as many times as necessary to close any unwanted holes.
Simple Choker effect
The Simple Choker effect shrinks or expands the edges of a matte in small increments to create a cleaner matte. The Final Output view displays
the image with the effect applied, and the Matte view provides a black-and-white view of the image with black areas indicating transparency and
white areas indicating opacity. Choke Matte sets the amount of choke. Negative values spread the matte; positive values choke it.
This effect works with 8-bpc, 16-bpc, and 32-bpc color.
Original (upper-left) contains unwanted edges after keying (lower-left) that are removed with Simple Choker (lower-right).
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