Quick ram question.

[Todd Kopriva]

Here’s a quick back-of-the envelope calculation.

4GB – (OS libraries and what the application needs to run) = ~3GB.

To prevent fragmentation and out-of-memory errors, 60% of the RAM left over will actually be filled with frames. That gets you to ~1.8GB. That 60% is a preference in After Effects CS3. You can increase it, but you do so at your own peril. There’s a reason that we removed that preference in CS4.

The reason for adding more RAM is not to increase your RAM preview length. The reason for adding more RAM is so that you don’t starve the background processes of RAM when you use Render Multiple Frames Simultaneously multiprocessing.

BTW, you mentioned the disk cache. Keep in mind that this has nothing to do with RAM preview. The disk cache is only used during standard preview (aka, spacebar play).
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Todd Kopriva, Adobe Systems Incorporated
putting the ‘T’ back in ‘RTFM’ : After Effects Help on the Web
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[Richie Tovell]

Cool todd, I enabled multiprocessing and my preview time about doubled, at a guess I’d say there’s about 3 gig being used by the preview.

With my ram cache set to %90 there doesn’t seem to be any underuning etc.

A 1080 by 1920 m2ts movie previews for about 1 min once set to half it’s resolution and I can work with that.

Thanks.

Richie.

[Kevin Camp]

i wouldn’t set the maximum ram cache value any higher than 60%. it will create stability issues. also, it you are trying to get longer ram previews, you are actually doing the opposite of what you are trying to accomplish.

decreasing the max ram cache will give you longer previews. the max ram cache is the ram available for processing, what’s left over is used for things like the ram preview.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Todd Kopriva]

Kevin is 100% right about the risk of stability problems.

But to the other point: The RAM cache is the part of the memory allocated to the foreground process that can hold rendered frames for RAM preview. The distinction is most clear when using Render Multiple Frames Simultaneously, because then that’s the only thing that the foreground process is doing—holding frames in the RAM cache while the background processes do the rendering.

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Todd Kopriva, Adobe Systems Incorporated
putting the ‘T’ back in ‘RTFM’ : After Effects Help on the Web
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[Kevin Camp]

oops.. i had some how switched it around in my head, i need more sleep…

thanks getting it straight, todd.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Todd Kopriva]

We certainly didn’t help the confusion by changing the preferences and terminology between CS3 and CS4. The After Effects CS4 preferences are much more clear overall, I think. But the change has caused some confusion.

By coincidence, yesterday I just happened to add a comment to the bottom of the “Memory & Multiprocessing preferences” page yesterday to try to clear up some of this confusion.

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Todd Kopriva, Adobe Systems Incorporated
putting the ‘T’ back in ‘RTFM’ : After Effects Help on the Web
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[Walter Soyka]

This doesn’t have anything to do with your RAM question, but you mentioned you were using an M2TS file. This format uses interframe compression, which isn’t ideal for After Effects. You should see better performance and results if you transcode to an intraframe codec first. See “Dave’s Stock Answer #1” on this forum for more on this.

Walter Soyka, Principal
Keen Live, Inc.
Presentation, Motion Graphics & Widescreen Design
RenderBreak: A Blog on Innovation in Production

[Richie Tovell]

So I’d need to re-render the m2ts movie files back to m2ts only using a different codec? Or would you sugest re-rendering the m2ts to a completly different filetype like AVI?

I’m still a little confused here as to what exactly you guys mean, if you mean I need to re-render to m2ts with a different codec What kind of codec would you recomend I use?

Sorry I havn’t used m2ts for long, or ever rendered an m2ts movie, I have a HDBlu-ray codec, but it doesn’t appear to be lossless.

[Richie Tovell]

I hear that, I’ve had nothing but griief from them, there are a load of my m2ts movies that After effects won’t even open (probably a hdcp issue) though.

I’d be glad to convert them to a different format, I’ll try rendering them as something like Quicktime or AVI, but won’t that increase the file sizes a great deal?

Thanks for the tips 😉 I’ll experiment a bit and see where it get’s me.

[Kevin Camp]

good catch walter…

richie,

you’d like to convert any codec that uses temporal (or interframe) compression to one that uses only intraframe compression for use in ae. you’re also going to want to render from ae to a codec that does not use temporal compression, or your image quality will suffer badly.

some common codecs that do not use temporal compression: uncompressed avi, quicktime lossless animation, quicktime photo-jpeg, apple’s pro res 422 (i think you need fcp), avid’s dnxhd (free from avid) and dvcprohd. you can also use any image sequence (tif, tga, psd, png, jpeg, etc.), but those, of course, would not contain audio….

it won’t make your ram previews longer, but ae will work considerably better (faster and more stable) if you avoid codecs that use temporal compression.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW