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After Effects Frame Blending Samples

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Adam FindlayAfter Effects Frame Blending Samples
by on Apr 13, 2010 at 2:36:47 am

Hey, Had a question I'd like to ask regarding Frame Blending in After Effects.

It'd be great if someone could set me straight on this. I - entirely as a hobby - edit clips from PC Games (think more along the lines of elaborate movies than crap 20 second long Windows Movie Maker clips). As PC Games tend to be optimised for achieving the highest possible real-time FPS, one of the things they lack is motion blur. Typically the solution to this is recording at very high framerate (240 or 480 depending on the intended final video's FPS) and using frame blending to artificially create it. The effect works quite well, although recently I've started trying much higher framerates (around 960fps for a project).

What i've noticed is that quite clearly, After Effects is not using all of the samples. 960fps should theoretically give 16 samples for 60fps and 32 samples for 30fps, however in either scenario, I can really only make out about 8, even after final export.

I was wondering if there was some setting somewhere limiting this, or if there is some inherent reason it can't use more.

What seems to happen is that instead of using all 16 samples for a period of time, it simply uses the 8 middle frames, which actually creates a worse result than a lower frame rate.

Anyway, hope this isn't too much of an essay, just wanted to make sure I got all the information out in the first post.

Thanks in Advance,

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Tudor "Ted" JelescuRe: After Effects Frame Blending Samples
by on Apr 13, 2010 at 10:19:27 am

If your clips from the games are encoded you may not actually get all the info in your frames (due to compression), thus there's no way for you to get the 16/32 bit info.
Dave LaRonde gives some great advice related to compression issues in Dave's Stock Answer #1 on this forum.

Tudor "Ted" Jelescu
Senior VFX Artist
Bucharest, Romania

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Adam FindlayRe: After Effects Frame Blending Samples
by on Apr 13, 2010 at 11:48:00 am

Thanks Ted, but I wouldn't have thought that would have been the problem. The video is captured from the game as a tga sequence along with a .wav audio file. I then encode these to lagarith (loseless) using VirtualDub. Also just to confirm, that is 8bit per channel video.

thanks anyway though.

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Bruce WainerRe: After Effects Frame Blending Samples
by on Apr 13, 2010 at 11:16:30 pm

try using the tga's as an image sequence directly - even a lossless format can contain temporal compression (one frame relies on a previous or upcoming frame to render) which throws AE off.

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Chris WrightRe: After Effects Frame Blending Samples
by on Apr 14, 2010 at 12:01:37 am

You must have a really beefy system if you can capture 960fps!

Revision's Reelsmart motion blur can add blur to any framerate. it's used for animation and re-blurring green screen objects.

It's possible that you're just seeing repeated frames of no motion which would appear as stutter because there's only so many discrete frames that the game engine clock uses. It's also possible that the recorder isn't accurate in its fps information versus actual targa dropped frames.

And finally the bug thing. In both Cs3 and Cs4 you can't interpret image sequences or create any compositions larger than 99 fps. I know, because I use this averaging trick to smooth out motion from timewarp interpolating.

In a nutshell, use one of these 3 options.
1. live with 99fps frame blended then decimate to 60 or 30 fps
2. use avisynth to decimate
3. get reelsmart motion blur

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