The Proxy features of Fusion work great for their simplicity, but sometimes you need a bit more control.  We’re all about the control…

Cropped compare of anisotropic proxy of a 4k plate

Along those lines, we’ve taken to using an inline proxy setup that provides some benefits over the built-in proxy.  It’s based around the assumption that tools take into account the pixel aspect ratios, which differs from the code branching that occurs with proxy, so you may not get correct results, but it’s also shows when tools are improperly handling pixel aspect ratios.

The general idea is that you scale the input by some factor, then divide the pixel aspect by that same amount.  Fusion handles the transformations just fine, knowing that an image that is 2048 wide, but with pixels that are .1 units in size is the same size as an image 20 pixels wide with pixels 10.24 units wide.

The image above shows a 4k plate proxied down to 12/24, meaning it is proxied in X by 12 (a value not available in the built in proxy) and the Y by 24 (the built in proxy does not allow anisotropy).  The filtering is done using the Catmull-Rom filter (filter options are not available to the built in proxy).

These advantages are minor, however, compared to the ability to:

1. Animate the proxy scale
2. Apply it to only select portions of your comp (or set it to be a different scale in different parts of your comp)
3. Preserve the cache of the input tools

I’ve attached a comp to demonstrate this.

(Hint:  Ctrl+1 resets the view scale/offset for A|B compares)