from Matthew's Apples
by Matthew Frederick Davis Hemming
January 2002
After recently completing work on my fourth High-Definition video, I thought I would pool some of my notes and experiences into a single document, for the potential edification of other After Effects-based compositors who may be considering taking on an HD project.
[ Technical Notes: In deference to reality, the results discussed below have not come from state of the art, super-cool, blazing-edge computers. Unlike journalists enjoying promotional models sent to them for evaluation purposes, many of us regular working stiffs use machines that are a year or two old. During the production of these videos I made use of a G4/450 (AGP) with 640 MB of RAM, a TiBook/667 with 512 MB of RAM, and a 9600/300 with 256 MB of RAM. The HD frame size was 1920 x 1080, running at 29.97 fps exported from Final Cut Pro 2.1. ]
First and foremost: do not be afraid.
Working in HD isn't nearly as punishing as you might imagine. I was surprised to find relatively simple compositions coming out of AE with render-times comparable to NTSC. While the HD frame is some 6 times larger in area than NTSC, I found that more complex compositions in general had render-times only 2 to 3 times longer. Occasionally, I had some nasty surprises (such as one shot that took 25 minutes per frame).
* The Filters
Usually, the deciding factor turned out to be the filters involved. Built-in Adobe filters fared the best. Fast Blurs, Tints, Levels, Glow, Displacement and others that are included in a default install of the AE production bundle work just slightly slower than in NTSC (e.g., sample frame fast blur of 16 pixels: at NTSC this takes less than 1 second on my TiBook, at HD it takes about 2 seconds).
Filters from third-party manufacturers were all over the map. Some of my DigiEffects filters turned to molasses (Aurorix 2), while others were as peppy as ever (Delirium). Boris was tolerably slowed, as were Final Effects filters. Puffin Image Lounge and Puffin Composite Wizard filters turned out to be a sneaky trap: they displayed reasonably well at lower resolutions, but turned into monsters when it came to full-quality rendering.
I was blown away with the performance of Ultimatte, which didn't seem to care that it was working at HD at all (three of the videos involved copious quantities of keying, so finding out that Ultimatte didn't scale exponentially was a real relief!). However, there was a hidden danger: when the key dug too deeply into the "uncompressed" Targa/Cinewave footage, it made visible cubic artefacting in a grid throughout the image. But don't panic: I only saw this phenomenon when trying to key semi-transparent elements like reflections, shadows and mist. Most of the time, Ultimatte behaved flawlessly.
* Memory
As everyone knows, when AE says it is "compacting cache" you often have time for dinner and nap before your RAM preview begins to build. This problem is ecsacerbated at HD resolutions. I found the best way to manage the problem was to keep my cache size much lower than normal (less cache to compact) and by purging the image cache fairly frequently (after every few RAM previews, for instance).
Since certain geometric transformations at HD resolution can put a major spike in your RAM usage, I found it necessary to keep the application's memory allotment high. For output, I generally assigned AE as much as it could take without strangling MacOS. As long as I made sure to purge my cache before rendering, I did not see the "creeping disappearance of free RAM" phenomenon during rendering.
In "low RAM" situations (i.e., less than 256 MB), I found that renders tended to become bogged down, slowing with each frame. I had to use virtual memory to give the 9600 a good 380 MB before it would cooperate in the rendering process. I found that the speed tax of VM was more than outweighed by the speed tax of rendering with too little memory.
* Drive Space
You knew there had to be a brutal part. It is the issue of drive space.
HD video weighs around 5.5 MB per frame. Do some quick math, and you'll see that a minute of HD weighs almost a gigabyte. When you include your source media with any process media and your final output, it suddenly becomes necessary to start counting in fractions of terabytes. And then you have to consider the duplicate media that you have to keep, even temporarily, when distributing renders across a network. All told, these four short videos (some 18 minutes of final media) and their associated files occupied a whopping half terabyte of disc memory on my systems (and that's not including all of the source material originally digitized by the editor).
But there's more.
Have you ever transferred 150 GB in a sitting? 100-BaseT Ethernet transfers were useless. Even with Firewire, HD file transfers invariably took much longer than expected. Occasionally, MacOS would choke and a transfer would have to start over.
* Tips
If you have an HD motion-graphics/effects/animation project in your future, here are my ten tips for a smoother ride.
1. Prior to beginning, clean up your computer to maximise drive space. Compact data and applications that you don't plan to use much for the duration of the project. Delete that directory of "temporary" items that the Finder says you created in 1991. If you don't have full confidence in your system's integrity, re-install your OS and key applications. You don't want to have to make a pit-stop mid-
project...where would you back-up 440 GB to?
2. Test each filter/plug-in rigorously at HD resolution before including it in your conception of the finished product. If it doesn't scale nicely, drop it from your plans.
3. If you're planning to use type be sure that you have an industrial strength font manager installed in your system to smooth those high-resolution jaggies. I used Adobe Type Manager Deluxe.
4. Assign lots of application RAM, but flush it frequently (Classic MacOS only).
5. Pre-render elements that reoccur frequently. Drive space is usually easier to spare than time.
6. Use raster art. I found that asking AE to rasterize vector art dynamically dramatically slowed things down (adding almost a minute per frame, in some instances). Try not to use over-sized raster elements though, as they just suck away RAM needlessly.
7. Avoid Motion Blur. Use where necessary, but sparingly. Motion Blurring several HD layers in AE can cause render-times to balloon. If you have to, pre-blur layers in Photoshop. If you're using a Directional Blur directly in AE instead, be sure to apply it to one adjustment layer rather than to several independent elements.
8. Visual details irrelevant in NTSC actually count! While working, check your frames at full-resolution/full-quality frequently. Minor misalignments can be crystal clear in HD.
9. If possible, render individual shots to be re-assembled in Final Cut Pro rather than long sequences. This minimises the trauma of a painfully long render or a crash. When queuing jobs up overnight, always queue easy jobs first and hard jobs last -- that way if AE is still stuck on a tough frame by the time you get up for breakfast, at least it took care of 12 other shots before getting jammed.
10. If you're planning some large file transfers, bring a book.
* Miscellaneous Notes
MacOS X
Incidentally, I experimented with rendering with After Effects 5.0 running through a 9.2.2 Classic environment in OS 10.1.2, and found that render-times were consistently somewhat shorter than rendering natively in System 9 (by a matter of seconds, usually). So, if you don't have After Effects 5.5 yet but are already (like me) finding it painful to boot up in System 9, don't fret -- you're not sacrificing anything when you run through Classic in X.
Additional Software
Besides Adobe After Effects and Photoshop, I also made heavy use of the Electric Image Animation System / EI Universe for creating set extensions for three of the HD videos. Render times for Camera under System 9 were amazingly fast, netting out at about 150% of comparable NTSC render times. Universe Camera running through OS X was at least 20 % faster.
People
The HD projects I mention here were part of work done for Toyota by Tele-Productions Mobile (www.tele-productions.com) of Toronto, Canada. The executive producer was Brian Blair; producer Sayumi Ito; director James Stewart; art director Darrell Martin; editor Daryl Jenkins. Their FCP-based HD editing system came from Extra Bytes (www.extrabytes.com). My name is Matthew Frederick Davis Hemming (www.mfdh.ca), and I am a freelance animator, illustrator and compositor (www.storyzoo.com).
