Proxies and Pre-Renders

Proxies and Pre-Renders

Any visual item in your Project panel can be set with a
proxy, which is an imported image or sequence that stands
in for that item. Its pixel dimensions, color space, compression,
and even its length can differ from the item it
replaces; for example, you can use a low-resolution, JPEGcompressed
still image to stand in for a full-resolution,
moving image background.

To create a proxy, context-click an item in the Project panel
and choose Create Proxy > Movie (or Still). A render queue
item is created and automatically renders at Draft quality
and half-resolution; the Output Module settings create a
video fi le with alpha, so that transparency is preserved, and
the Post-Render Action uses the Set Proxy setting.
 shows how a proxy appears in the Project
panel. Although the scale of the proxy differs from that of
the source item, transform settings within the comps that
use this item remain consistent with those of the source
item so that it can be swapped in for fi nal at any time. This
is what proxies were designed to do, to allow a low-resolution
fi le to stand in, temporarily and nondestructively, for
the high-resolution final.

By default, the source fi le or composition is used to render
unless specifi cally set otherwise in Render Settings > Proxy
Use. Choosing Use Comp Proxies Only, Use All Proxies, or
Current Settings options  allows proxies to be
used in the fi nal render. To remove them from a project,
select items with proxies, context-click (or go to the File
menu), and choose Set Proxy > None.

Similar to proxies, but with a different intended use, are
pre-rendered elements. With a composition selected,
choose Composition > Pre-render and a moving image fi le
is set to render at Best quality, full resolution; the Import
and Replace Usage is set for the Output Module.
You don’t have to follow this usage; I have made proxies
behave as pre-rendered elements and set my Render Settings
to Current so I can choose whether to use the proxy
or re-render. Managing that process, however, adds an
extra set of steps.