Travel Matte - Luma
The Travel Matte - Luma composite mode does the same thing as the Travel Matte -
Alpha composite mode, but the transparency is derived from the luma information
(instead of the alpha channel) of the clip below. The luma information may be derived
from a grayscale equivalent of the RGB channels, or directly from the luma (Y´) channel
in the case of Y´C
video. White is equal to 100 percent transparency and black is
equal to 100 percent opacity (solid).