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RAM Preview Question - Am I doing something wrong?

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Shawn MarshallRAM Preview Question - Am I doing something wrong?
by on Nov 16, 2011 at 1:46:28 am

Hi:

I'm trying to speed up RAM previews that encompass multiple video layers by lowering the resolution of the comp to 1/8 or even 1/16th, but the time it takes to calculate the preview varies little regardless of the resolution (except compared to Full resolution). Am I missing a setting somewhere?

I've finally upgraded my OS from Leopard to Snow Leopard, and along with that I'm finally moving full time to AE CS 5. Up until now I used CS 4 for all of my work because I wasn't happy with some of the changes made in AE CS 5. Last summer I posted several threads lamenting the elimination of the Wireframe Preview function in AE CS 5 and CS 5.5. I found that the Wireframe Preview was an invaluable tool for quickly roughing out the motion of multiple video layers, synced to sound. Once I had the general motion worked out in Wireframe Preview I'd then use the regular RAM preview for final refinement. But I was informed by Todd Kopriva that no one used that feature, and so Adobe dropped it from the 64-bit rewrite of AE CS 5.

In an earlier thread Todd says "... why not do your RAM preview at 1/8 resolution? If a RAM preview at half resolution took 2 minutes, then one at 1/8 resolution would take ~10 seconds, the same amount of time that you say the wireframe preview took."

So I've just run some tests, and it's not working the way Todd describes. I've set up a 1920x1080 29.97 fps comp with twenty video layers: 5 at 1920x1080, 12 at 1280x720, and 3 at NTSC resolution. All of the clips are ProRes codec Quicktimes playing from an internal SATA RAID 0 on my 8 core Mac Pro (circa 2008) with 10GB of RAM. The array can read and write at around 230 MB/sec.

I've arranged the 20 video layers in 3D space, parented them all to a null, and I have the null moving towards the camera for 150 frames to fly the layers past the camera. There are no lights or motion blur.

A Wireframe Preview in CS4 takes less than one second to calculate and start playing the 150 frames. I can get a good sense of how fast the video boxes are moving and their relative motion to each other.

Now for a RAM preview in CS 5: At Full resolution it takes around 165 seconds to render 150 frames. At Half resolution it takes around 97 seconds. At Quarter resolution it takes 94 seconds. At one-sixteenth resolution it takes around 90 seconds. I'm not seeing the predicted increase in speed as the resolution decreases. Maybe that would work with static files, but it doesn't appear to do much for Quicktimes sources.

It seems that even though I've specified lower resolutions CS 5 acts like it's bringing in each frame off the drives at full resolution, then displaying the frames at 1/2 or 1/4 or 1/16.

I'm thinking my best alternative to the Wireframe Preview might be to temporarily freeze each video layer while I set up the motion. Once I've got it roughed out I can disable Time Remapping on those video layers. RAM previewing the above comp with all of the video layers frozen takes 7 seconds to render at half resolution. That's acceptable. The problem will be if I'm Time Remapping those video layers freezing those layers will screw that up.

This all still strikes me as a lot of rigamarole to go through to regain the functionality of this eliminated feature.

Any other suggestions?

Thanks for reading.

Shawn Marshall
Marshall Arts Motion Graphics


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Walter SoykaRe: RAM Preview Question - Am I doing something wrong?
by on Nov 16, 2011 at 1:40:24 pm

[Shawn Marshall] "It seems that even though I've specified lower resolutions CS 5 acts like it's bringing in each frame off the drives at full resolution, then displaying the frames at 1/2 or 1/4 or 1/16.

I'm thinking my best alternative to the Wireframe Preview might be to temporarily freeze each video layer while I set up the motion. Once I've got it roughed out I can disable Time Remapping on those video layers. RAM previewing the above comp with all of the video layers frozen takes 7 seconds to render at half resolution. That's acceptable. The problem will be if I'm Time Remapping those video layers freezing those layers will screw that up."


Don't use Time Remapping -- use still images as proxies [link] instead.

That's the closest you'll get to wireframe preview.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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Shawn MarshallRe: RAM Preview Question - Am I doing something wrong?
by on Nov 16, 2011 at 7:39:00 pm

Hi Walter:

Thanks for taking the time to reply, I appreciate it.

Unfortunately, as far as I can tell, there's no magic "Make proxy stills of every selected item and link them to their original footage" button. I'd have to render out a frame of each piece of video and then link those stills as proxies. At some point the effort required to go through such a workaround will outweigh the time it takes to just let the RAM preview churn through all the frames of moving video. With a Freeze Frame I can select all 20 layers at once and freeze them all. This only takes a few seconds. I can then just as quickly unfreeze them all when I'm ready to use the moving video.

It's not like every project I do involves flying around a bunch of video boxes, but for those handful of projects we get each year requiring that, the Wireframe Preview really came in handy.

Cheers.

Shawn Marshall
Marshall Arts Motion Graphics


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Walter SoykaRe: RAM Preview Question - Am I doing something wrong?
by on Nov 16, 2011 at 7:55:32 pm

[Shawn Marshall] "Thanks for taking the time to reply, I appreciate it."

I'm happy to help. I know how important wireframes were to you, so I hope I can help ease you through your loss. :)


[Shawn Marshall] "Unfortunately, as far as I can tell, there's no magic "Make proxy stills of every selected item and link them to their original footage" button. I'd have to render out a frame of each piece of video and then link those stills as proxies. At some point the effort required to go through such a workaround will outweigh the time it takes to just let the RAM preview churn through all the frames of moving video. With a Freeze Frame I can select all 20 layers at once and freeze them all. This only takes a few seconds. I can then just as quickly unfreeze them all when I'm ready to use the moving video."

Check out rd:Approximate [link]. It's the magic button.

The main reason I suggest using proxies here is that AE will ignore proxies during render unless you explicitly tell it to use them in a render item's Render Settings. You can't do a "Best Settings" render and accidentally include the proxies you were previewing with.

With time-remapping, you could forget to turn off a layer and botch a render. Also, it'll be really inconvenient if you actually have to use time-remapping for that layer in final render.

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog - What I'm thinking when my workstation's thinking
Creative Cow Forum Host: Live & Stage Events


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