Multiprocessing begins working well then goes back to one frame at a time

[Darby Edelen]

[Nicholas Shera] “Now, when I render a really complex project with multiprocessing, initially I can see that several frames are rendered simultaneously and it all goes wonderfully. But sometimes the multiprocessing stops, and then only one frame is rendered at a time. When this happens, I see the active RAM plummet in the Activity Monitor. I can remedy this by clicking the RAM preview button to stop the rendering, then clicking it again to restart it. The rendering then continues on, going back to the multiprocessing as it should.”

This sounds a little confusing. Are you talking about rendering through the render queue or a RAM Preview?

Darby Edelen

NVIDIA
Santa Clara, CA

[Nicholas Shera]

I’m talking about BOTH. That is, the problem sometimes occurs when making a movie through the render queue, and sometimes with a RAM preview. I am wondering whether it’s because I sometimes have other applications running at the same time (which I might use), that somehow interfere with the multiprocessing. Nothing major, mind you, only programs like iTunes, Safari, Mail or Word. However the problem often occurs well before all of the free RAM is used up, so it’s not like the other applications are robbing AE of RAM.

[Kevin Camp]

you could try the preference hack to limit the number of processors available to after effects:

1. Quit After Effects.
2. Open the After Effects text preferences file, Adobe After Effects 8.0 Prefs.txt, located in the following folder:
Mac OS: Users//Library/Preferences/Adobe/After Effects/8.0
Windows XP: C:Documents and SettingsApplication DataAdobeAfter Effects8.0
Windows Vista: C:UsersAppDataRoamingAdobeAfter Effects8.0

3. Find the [‘MP’] section.

4. Change the “MaxNumberOfProcesses” value to “6”. — you can vary this setting, you just want it to be less than the number of cores that you have. some say to limit the cores to half the gb of ram that you have (allowing 2bg of ram for each core for optimal performance).

5. Save and close the preferences file.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Nicholas Shera]

Okay, thank you for this suggestion. I will try it next time.

[Thai Tran]

There is a script called Throttle over at AEscripts.com that allows you to adjust the MP attributes of AE on the fly. You can turn it on or off as well as specify how many cores to use. Other options include the ability to switch from 8 to 16 to 32 bit (even though you can do this by option+clicking on the “8bpc” in the project window. AND it allows you to turn on Idle Rendering, which allows AE to continue rendering when you are parked on a frame if you switch to another app.

There is also a variant of the script which puts a purge button at your disposal. However, you can use Option+Apple+Slash(num pad) shortcut to do that same thing. Good if you don’t want to memorize the shortcut.

“If at first you don’t succeed, destroy all evidence that you tried in the first place.”