December 2, 2009

AE FAQS: memory usage, gamma shifts + more

Today Todd Kopriva added some useful posts on FAQs for After Effects and ProRes 4444 colors and gamma shift when working with After Effects and Final Cut Pro [Todd later added more on ProRes on the AE-List].

Many of us will find these reminders useful, like FAQ: Why doesn't After Effects see and use all of my RAM? In another example, here's a portion from RAM and disk caches that explains counterintuitive memory use of new systems with 8 GB and more of RAM:

"In the Memory & Multiprocessing preferences, After Effects reports the size of the RAM cache---the amount of RAM that can be filled with frames for RAM preview. With Render Multiple Frames Simultaneously turned off, this value is reported as Total After Effects Memory Usage. With Render Multiple Frames Simultaneously turned on, this value is reported as Foreground Memory Usage.

This value will not be the full amount of RAM allocated to the foreground application. Rather, it is just the part that can be filled with frames for RAM preview.

For example, on a Mac, this value might be 1.79GB on my Mac. 4GB is the theoretical limit for an After Effects process (because it's 32-bit). The OS takes a bite, getting you down to ~3GB. The RAM cache is only allowed to use 60% of that, which gets you down to 1.79GB.

The limitation of the RAM cache to 60% of the memory allocated to the foreground process is to avoid fragmentation problems and therefore out-of-memory errors.

The terminology can be confusing in part because in After Effects CS3 we had a Maximum Memory Usage item and a Maximum RAM Cache Size item, and in After Effects CS4 the thing called Foreground Memory Usage maps more closely to the latter, not the former."

Update: it's December and Todd is back with a reminder on RAM, Performance tip: Don't starve your software of RAM.

No comments: