User Guide

CHAPTER 3
98
Building a Composition
About placeholders and proxies
When you want to temporarily use a substitute for footage, choose one of two alternatives:
a placeholder or a proxy.
Placeholder A still image of color bars used to temporarily take the place of missing
footage. Use a placeholder when you are building a composition and want to try out ideas
for footage that is not yet available. After Effects generates placeholders automatically, so
you do not have to provide any placeholder footage.
Proxy Most often a lower-resolution or still version of existing footage used to replace the
original to save processing time. Use a proxy when you have the actual footage but you
want to speed up previewing or rendering of test movies. You must have a file available to
use as a proxy.
Using either method, any attributes and keyframes you apply to the placeholder or proxy
are transferred to the actual footage when you insert it. You can even set a proxy for a
placeholder, so that you use a low-resolution or still version of full-resolution footage that
is not yet available. See “Working with missing source footage” on page 98 and “Substi-
tuting a low-resolution proxy for footage” on page 99.
If final footage is unavailable, and you simply want to substitute draft footage or a story-
board still image, you can import the draft footage and replace it with final footage later.
Working with missing source footage
If After Effects cannot find footage when you open a project, it appears in the Project
window labeled Missing, and the name of the missing footage appears in italics. Any
composition using that item as a layer replaces it with placeholder color bars.
You can still work with the missing item in the project, and any effects you have already
applied to the missing layer remain intact.
If you replace the placeholder with the actual footage, it returns to its correct place in all
the compositions that use it. See “Substituting a placeholder for footage” on page 99.
UG.book Page 98 Wednesday, February 21, 2001 12:05 PM