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You can’t figure this out – Unusual Key/Other Issues
I am having an issue with a keyed footage in a project that only appears on output. Here are the specifics of the project and workflow.
I received a Quicktime movie that was exported from Final Cut at 23.98 ProRes422 and 1280×720. Unfortunately I don’t have Automatic Duck, so I manually cut the sequence into individual layers for each shot, as opposed to importing the FCP project into AE. I then applied Keylight to a duplicate of the original layer and set it as a luma matte. I then added the Spill Suppressor effect to the original layer. Possibly noteworthy is the fact that this is a 16 minute edit, and my AE comp for the key had about 230 layers.
I then passed this AE comp over to the motion graphics guy here. His AE comp settings match mine. (We are both using CS3 on Intel MacPros.) He imported my AE comp into his master comp for the project and built all of the graphics around it.
Everything looks great in AE, the key, the color correction – everything. After exporting the rough from AE (Animation codec, 23.98fps, 1280×720), the problems arise.
The first and greatest issue is that the key looks horrible. It looks like it would if you were scrubbing though the timeline and seeing it before RAM preview has cached a particular frame. It’s only on the edges. It looks similar to an interlacing issue, but it only appears around the edges.
Second issue is possibly in the color correction. These effects aren’t keyframed, but when I play back the rendered QT file it starts acting quirky. A few seconds into the video, the color correction (Levels, Hue/Saturation) go from being inactive to active. At this same time the harsh edges appear. There are also a few masks that seem to change there position.
We’ve tried rendering out the AE project that only contains the keyed footage, and then bringing that into AE. The harsh edges then appear.
Any solutions? I’m banging my head against the wall and getting nowhere fast.
-Andrew Saliga
Steelehouse Productions
http://www.steelehouse.com -
3 Replies
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first off, in fcp, 23.98 fps is actually 23.976 fps, so make sure that in ae, you are working with it at 23.976 fps (for your comps and renders).
also, you should search the posts for color issues with fcp and ae, there are some settings or steps to use to avoid color shifts between the 2 apps… i’m not sure if this is actually your problem, but it may help.
the jaggy edges could be an interpret footage problem in ae. if the 23.976 footage (either the original, or the keyed render) was somehow misinterpreted by ae as interlaced, then ae may be trying to separate the fields and that would create bad edge artifacts. select the clip in the project window and choose file>interpret footage>main to see change ae is interpreting the clip.
another potential issue with 24p, is that the footage was captured and exported from fcp with a pulldown. ae can remove the pulldown, but if the footage had been edited with the pulldown, then exported from fcp as a single clip (i.e., multiple shots as a single clip), then you will have a clip with a mixed pulldown cadence which ae will not be able to remove the pulldown. you’ll need to split the clip at the edits and import each shot as an individual clip to remove the pulldown.
for color issues aside from fcp-ae color management problem… most color correction efects in ae are opengl accelerated. opengl is a little unstable in ae, and can behave erratically. so check preferences>previews to make sure that opengl is disabled for previews to prevent opengl from being used.
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
Try changing the render settings in After Effects to…
Output Module> Video Output> Color: STRAIGHT (UNMATTED)
It defaults to “color: Premultiplied (matted)” which does some funky things to alpha channels and their borders.
Production Associate
Bend, Oregon, United States -
Kevin,
Thanks for the extremely thorough advice. Some of the potential causes of the problems I had tested, but others like checking the cadence and OpenGL, I had not.
Dan,
Thanks for your input as well. These renders were set up to be “Straight” renders. I never knew it could cause issues with alpha channel edges though, so I’ll look for that in the future.
After much testing we found the source of the problems.This is a 16 minute long HD clip with Keylight and various other effects applied. Keylight was crashing the render every time, and they were also taking a long time. To remedy this I set up AE to purge frames (under the “secret” menu) and also enabled multiple processors. This improved render speeds and prevented crashing. There were also other miscellaneous tweaks I had made to the settings.
In order to figure it out I back-tracked with the the motion graphics guy here and reverted only one setting change at a time. The one that made a difference was enabling multiple processors! When we unchecked the box, thus disabling it, the renders looked great after coming out of AE. No idea how or why this happened, but it worked.
In the end we just rendered the AE timeline in segments and then cut it together in FCP.
Thanks again for all of your help.
-Andrew Saliga
Steelehouse Productions
http://www.steelehouse.com
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