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Old October 23rd, 2007, 09:12 AM   #1
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An AE RAM problem, help!?!

I've been working on some CG elements for addition into a live action scene, and it's been going well. I've got 6 layers, 4 of which are different bits of the live action, the other two are 2 different shot-angles of the CG action--mostly alpha info with small bits of CG animation. It previews, and RAM previews, just fine...with the exception of the occasional 'drawing error' when scrubbing that seems to be non-fatal.

The system is a ~2.8 GHz P4 hyperthreaded, 2 gigs RAM, running XP home with a SATA-300 160Gig working drive (~30 gigs free as of last night); I've not had notable computing-power problems before.

Anyway, the system has begun giving "out-of-memory" errors when I run the full-length render. I'm only talking about 16 seconds with a bit of layering here. What I've noticed is that the Render panel's "RAM:xx% used" readout counts up sequentially: with each new frame there is progressively less RAM available until it finally can't get any more and pukes.

Anyone know how to keep this from happening, or what I've done wrong?

The docs tell me that AE only 'needs' enought RAM to render a single frame (composing all of it's layers) at any one moment, which says to me that it should not be stacking up data like that in the RAM. If I purge the image cache, I can restart the render until it quits again, so I think I'd like to shut the cache off during output render; I just don't see how to go about that.


thanks in advance,

andy
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Old October 23rd, 2007, 01:34 PM   #2
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Is this an isolated issue with the rendering preview? (ie, when you press space bar), or is this a problem with exporting as well?
Try using the 0 on the number pad, or fn+m if you have a laptop style keyboard; that will do a render slightly differently than the normal preview and may work around this. Either way, it'll be a bit more info.
And, of course, try "make movie" to see if that can work.


The only other thing that comes to mind is restarting to be sure it has cleared any random stuff that is hogging ram, but I assume you've tried this, probably a few times.
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Old October 23rd, 2007, 03:37 PM   #3
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Thanks for the thoughts, restarting seemed to help at first but I've been adding more & more complexity to the CG footage layers and now it no longer makes it all the way through the comp. I've made restarts and OS optimizations part of my process on this project.

I can stop the render before it gets to that critical RAM percentage, purge the image cache, and restart rendering...but I never had to before, and shouldn't.

It acts like a memory leak, which used to happen-- like, windows 3.1 era-- when crappy software lost track of the data it was managing, but AE seems to be aware of and OK with it: AE has a counter showing how much RAM is in use during the render, and as that counter approaches 60% (which it really shouldn't on such a simple comp) it always craps out: "out of memory error." The system monitor shows the page file growing too, during all this.

It's only an issue with the 'make movie' output render. That's what is so puzzling: previews run (mostly) fine, and they are //supposed// to be filling up the RAM to run at real-time speeds. Maybe it thinks I want it to make a preview render at the same time as my make-movie output, and the memory requirements are conflicting? I've not seen such a setting in the software, but that's why I come to the experts here...

I'm going to mess with the physical box tonight (re-seat the RAM, and such). See if that helps here or with my other AE issue. (ref my Keylight thread) Something seems fishy. I've also got 2 different pairs of RAM dimms, so maybe that's the issue. (each pair is a 'match', but the 2nd pair is of a totally different vintage...)

andy
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Old October 24th, 2007, 09:27 AM   #4
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Hi,
Have you tried the OPENGL hardware preview rendering, it works better. But first the video card should support it (Quadro is recommended). I have had similar issues earlier, but after the update of the workstation (Intel Quad Core, Quadro FX 1500 and 2 x 1GB identical RAM) the problems are almost gone, however sometimes if the comp is too complicated I still run into memory problem. I already ordered 2 x1GB more RAM to solve the issue. Maybe the problem is AE software specific?

Margus
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Old October 24th, 2007, 09:31 AM   #5
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Got it!

AE defaults to use 60% of RAM as the "image cache"->"maximum RAM cache size". For whatever reason, I was crashing above 58% (sometimes it would make it to 60+%, I don't understand that variation...). So I bumped the setting down to use 50% of RAM instead, so it never gets to that rough patch in my RAM (whatever its nature); problem solved.

It seems like AE carves out a space in the RAM, and uses it all up (keeps rendering frames into RAM until the cache get full) before over-writing its earliest entries. I didn't notice any slow-down for having 'less' RAM available. As long as there is enough RAM allocated to render a few frames (the most memory intensive frames, in particular), AE won't need to use the disk cache during make-movie rendering.

Last edited by Andrew J Morin; October 24th, 2007 at 03:15 PM.
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Old October 24th, 2007, 09:38 AM   #6
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Margus,

I'm using on-board intel video, which shares regular system RAM. ( Now that you mention it, that may have been part of the trouble all along... ) Last time I tried the OpenGL setting, it gave me some trouble. However, having solved my current issue, perhaps I will try it again: I'm sure you're correct that-- if it works at all-- it would be better to use the video processor as much as possible for rendering.

thanks for your input!!

andy

PS Considering your problem (and proposed RAM purchase), I wonder if my solution in my post above would help you, and save you some money? Not that I would councel anyone NOT to get more RAM...

Last edited by Andrew J Morin; October 24th, 2007 at 03:14 PM.
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Old October 25th, 2007, 09:28 AM   #7
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Thanks Andy, I will check my memory settings.

Cheers,
Margus
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