After Effects Glossary

CGI
See ‘computer-generated imagery’.

compositing
This is the proper term for what’s known as ‘keying’, but as keying seems to be the word used more often please see that definition.

computer-generated imagery (usually abbreviated to CGI)

frame rate
The frequency at which each consecutive image (frame) of a film appears per second (so it is measured in frames per second or FPS). The general consensus I’ve found online is to work in 24p unless the project demands otherwise. 24p is standard for films you’ll see at the cinema (the ‘p’ stands for progressive image storage, as opposed to interlaced video). 25p is standard for UK tv/PAL, and in north America they use 30p (NTSC). By the way, you may remember a big deal was made of the Hobbit being filmed in 48p, but when it actually came out this made the film look like a low budget 80s soap opera, because their hyper-real quality also came from higher frame rates.

frames per second (FPS)
See ‘frame rate’. Note that in notation this is written as ‘p’ (for progressive image storage). So 24 frames per second is written 24p.

keyframe
In traditional animation, the keyframe was the start or end point of any smooth transition. In After Effects, you define the start and end point keyframes and the program will fill in the smooth transition itself (‘interpolate’).

keying (properly known as ‘chroma key’ or ‘compositing’)
This usually means using a green screen (or blue screen) to artificially place an actor in another environment, a technique used for everything from weather reports to Star Wars. The environment could be a moving image or a static one (see ‘matte painting’). After Effects replaces a very narrowly defined colour range with another image. In its most sophisticated form, the camera angle moves so that our view of both background and actor seamlessly alters.

matte painting
A digital painting of a landscape or environment placed behind an actor by keying. This can be static or (3D) animated. Before digital technology the matte painting was an actual painting on glass placed behind the actors.

matting
I think this is now used as a synonym for ‘keying’. The term comes from the pre-digital era, when combining two moving images required part of the film stock to be masked out (the mask is called the ‘matte’ or ‘traveling matte’, a specially altered duplicate shot) so that a second film can be superimposed on another without causing double exposure. Because the process required five separate strips of film it often resulted in ‘halos’ around different elements, modern digital matting does not have this problem.

motion graphics
This is a very broad term, but in After Effects just seems to be a synonym for ‘animation’.

non-linear editing
The meaning of non-linear editing is still unclear to me, it seems to just mean ‘editing’. When physical film was used, all editing was linear because you have to run through the film from beginning to end to find the piece you want to edit. In the digital age with a digital file you can jump to any point you want in the film, and copy/cut-paste.

plug-in
Just like Photoshop, there are loads of plug-ins available for After Effects. These are third-party created software that add a new feature to AE. These plug-in features includes things such as rigging, weather effects (rain and snow), 3D geometric effects etc.

post-production
A very broad term for any part of the film making production process that occurs after the live action footage has been shot. This includes video editing and creating the soundtrack, and anything you do in After Effect (I guess this is where the software got its name – creating the visual effects after (post) live footage).

rigging (aka ‘skeletal animation’)
A computer animation term where characters and objects are made up of a skin (‘mesh’) over a skeleton (‘rig’). The mesh is how the thing looks, the rig (the skeleton) controls how the thing moves. Each bone of the rig has three properties; position, scale and orientation. There is also the option of a parent bone, so that the rig has a hierarchy (the hand bone is connected to the forearm bone, when you move the forearm the hand moves with it).

Winona Ryder in A Scanner Darkly
an example of rotoscoping – Winona Ryder in A Scanner Darkly

rotoscope, rotoscoping
Creating animation by tracing over live action footage. The first time I saw this was in the film A Scanner Darkly, though the process has been around for over a hundred years.

tracking (aka ‘camera tracking’, ‘motion tracking’ or ‘match moving’)
Combining computer graphics and live action footage so that both graphics and live action move seamlessly.

transcoding
The transfer of audio or video files from one format into another. It is usually a lossy process (= causing generation loss of quality).

visual effects (abbreviated to ‘VFX’)
A broad term for any creation or manipulation of footage that is not a straight live action shot. It seems to refer more to the integration of live action footage and computer generated imagery, or computer generated imagery that simulates and is edited into live action footage. I assume this means things like animation, programme logos and so on created in After Effects are not strictly ‘visual effects’.

VFX
See ‘visual effects’

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