Containers that group several objects in a Motion project. Layers can be nested inside other layers. Filters and behaviors applied to a layer will affect all the elements contained within it. Known in other applications as precompositions.
letterbox
The display of video to fit within a standard 4:3 monitor, resulting in a black bar at the top and the bottom of the picture.
Library
A pane in the Utility window in which you can search for Motion content such as behaviors, filters, particle emitters, generators, fonts, Favorites, and additional content.
linear editing
A video-editing style in which a program is edited together by copying shots from the original source tapes to a master tape, one by one. Because the assembly is linear, any changes made to an earlier point on the tape result in the rest of the edited tape having to be reassembled from that point forward.
See also [nonlinear editing]
looping
Repeated playing of the playback range. On by default.
low-key images
Images that are made up of mostly dark values.
luma
Short for luminance. A value describing the brightness information of the video signal without color (chroma). Equivalent to a color television broadcast viewed on a black-and-white television set.
Luma Key
A filter used to key out a luminance value, creating a matte based on the brightest or darkest area of an image. Keying out a luminance value works best when your clip has a large discrepancy in exposure between the areas you want to key out and the foreground images you want to preserve.
