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Fun with Gamma, Quicktime and After Effects

By Mark Christiansen | October 31, 2007

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Here's a scenario being replayed at studios around the globe: The decision is made to upgrade to After Effects CS3. A big project comes in. All proceeds quite well until it's time to render for final output, at which point files coming out of After Effects - particularly those being edited in Final Cut Pro - appear darker, even when rendered with a codec traditionally thought to be "safe" for gamma such as Photo-JPEG or even Animation (as was used to create this image). Howls of pain and gnashing of teeth ensue, After Effects is blamed, and in at least one case the entire studio reverts to 7.0. True story.

Don't let this happen to you, folks.

Although there are various permutations of this problem, it generally comes back to rendering Quicktime movies directly from After Effects. "Why is After Effects messing with my Quicktime output?" you might ask. "Why doesn't it just work like in previous versions?"

The short answer is that a simple checkbox may help you. Open Project Settings in After Effects CS3 and under Color Settings, toggle Match Legacy After Effects Quicktime Gamma Adjustments. This causes After Effects to work with QuickTime movies the same way as previous versions of After Effects. Boom. No need to set a Working Space or mess with gamma in any other way.

The longer answer is that gamma in Quicktime has essentially always been unpredictable for a couple of reasons: Apple changes the gamma according to their perception of how you're viewing it (i.e. which platform you're on, whether it's a web codec, and what application is being used) and, being Apple, they haven't published their gamma settings so that anyone else knows what the heck is going on, other than empirically.

Oh, don't get me wrong Apple, I'm typing this on a MacBook Pro running Leopard, an iPhone at my left hand, Mac Pro behind it, ready to send this post via Airport Extreme.

I will likely have more to say on the subject of color management and I/O in After Effects, also a huge topic for the new edition of the book. Meanwhile, please freely post your horror stories (or revelations) here and I will scan them for more specific points to address. There's also more to say about Quicktime and how it handles (or doesn't) things like aspect ratio.

If you're feeling bitter, boycott Quicktime until Apple and Adobe work this out together and use image sequences instead, like your pals who are film professionals.

By the way, here is a post from FreshDV a couple months back showing another culprit feature for unpredictable Quicktime gamma, in Quicktime 7.2's very own preferences.

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Comments

glennser: | February, 12, 2008

Great post, I’m a huge fan of your books and can’t wait to get the latest one.
We’ve had so many disasters due to quicktime gamma issues, that and YUV-RGB conversion gaffs that, as you point out, the pro’s have known about for years and either work around it or use another format.  Personally I’m disgusted that Apple has never sorted this out, they push the pro apps and QT as a pro production format and then pull lame stunts like changing code overnight so it works better with iTunes or the web, and I’ve heard from several third party developers that only a very select, chosen few get beta or pre-release stuff, the others just have to scramble and apologise to their customers when something gets hosed by an Apple update. And why don’t they publish how this stuff works? Why can’t we just have a checkbox for the gamma?
This is a bit of a rant but I’ve been praying for years for someone to come up with a suitable alternative to quicktime, don’t get me wrong, I love quicktime, it has so many great features but I really can’t consider it a pro format purely because of the unprofessional way Apple release updates and change the code.  I forget which update it was (about 4yrs ago) that killed all our decklink/aja systems, renders would randomly switch to lurid greens and purples, turns out Apple knew about it and had gone to the bother of writing an uninstaller (whippeee!! an uninstaller, imagine it!!). Did they warn anyone not to install the update if you work with YUV though?  Oh no, you had to hunt around for ages till you finally found the tech note and uninstaller buried on the support pages somewhere.
(I did warn you this was going to be a rant).
If you want a good laugh check out the forums regarding frame accuracy when laying off to tape from FCP, it will randomly be off by a single frame, some shops point a handicam at the deck monitor so they can rewind to see the burnin to make sure the slate’s correct without waiting for the whole thing to finish… insane, and this goes for dBeta, D5, HDCamSR, with or without house sync, I noticed it first in FCP2.
In my opinion Apple users are way to forgiving, it’s seen as bad form to point out the bugs because we’re the “underdogs” and don’t want to give ammo to Avid users, stupid.
Now colour profiles in QT are really freaking me out, I loved it that AE just read the native values before, to me colour profiles seem like a great idea if everyone knows what they’re doing but from what I’ve seen in static files they lead to more problems than they solve, does FCP see the embedded profiles? How do we know they’ll interpret them correctly?
What I’d really like to know is whether anyone forsees a replacement for QT on the horizon?  Image sequences are just such a pain when you’ve got a lot of animations to deal with, plus no audio, avi doesn’t really work on the mac and doesn’t have any free, lossless codecs like QT animation, does it support timecode either? Anyone have good experiences with DPX, MXF (apart from acquisition), AAF?
Thanks, if you’ve made it through my little rant any thoughts/sympathy appreciated,
Glennser

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