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Image flicker on x-axis 2.5D camera moves

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Jason BaldariImage flicker on x-axis 2.5D camera moves
by on Nov 9, 2011 at 11:07:28 pm

Hello community,

I have a project here with a very large scale 2.5D environment that I'm animating a camera through. Several of the layers in the environment which are featured prominently (high res cut outs of people) are exhibiting a 'flickering' when played back on a production monitor.

The Facts:
- I'm on a CS5 system.
- The flicker can be described as a 'slight jittering back-forth motion' when the output is played in RT
- The anomaly is only when close up to the person layer
- The anomaly is only apparent when the main camera motion is on the X axis (there is plenty of Z movement as well - this doesn't seem to affect it)
- I've tried setting my comp motion blur shutter angle at 180 and even up to 360. It is still there.
- I've applied the 'Add Alpha' blend mode to the layers. It is still there.
- I originally rendered out to h264, but just in case it was the codec, I tried ProRes 422HQ. It's still there.

- One thing I haven't tried is upping the number of samples per frame on my motion blur, or trying to change the shutter phase. Do you think this would make a difference?

I'm ready for HAL to open the pod bay doors and suck me out... please advise if you can. Thanks!

Cheers,
-Jason


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ben g ungurenRe: Image flicker on x-axis 2.5D camera moves
by on Nov 10, 2011 at 4:37:49 am

if you're only seeing it on a monitor, it sounds to me like your monitor is displaying the image with fields and your video is outputting frames (no fields). Another possibility is that your project is 24, the monitor is playing 30 and thus adding 3:2 pulldown, but has the field order backwards....

Have you tried rendering out the animation and previewing it via a video editor? Or burning to DVD/BluRay and watching it?

Ben Unguren
Motion Graphics & Editing
http://www.mostlydocumentary.com


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Jason BaldariRe: Image flicker on x-axis 2.5D camera moves
by on Nov 10, 2011 at 4:56:39 am

Thanks for getting back to me Ben.

As it turns out, the anomaly is present in QTs as well, and can be seen on a computer monitor, though it's harder to see. For tests, yes I did play it through FCP and a DaVinci, all from a 23.976 timeline to an HD broadcast monitor with matching frame rate setting. I also rendered out about 20 tests since that last post with all possible variants in motion blur settings, footage interpretation, interlacing, and the reduce flicker filter- all with the same result :/

This particular project is a the latest volume in a series we've done in years past. We wound up putting a similarly animated title from a few years ago in the blu ray player to see if the anomaly was present on much older outputs that made it to the marketplace, and there it was. The conclusion - it's just the way After Effects renders. 'normal' I guess.

It's not horrible or anything. It's just something noticed by perfectionists (myself and the room of onlookers all). One of those anomalies that comes up every few years. The last time I saw it was around '05, and I don't remember finding a workaround then.

Anyway, you have my thanks.
-J

Motion GFX & VFX
http://www.jasonbaldari.com


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Michael SzalapskiRe: Image flicker on x-axis 2.5D camera moves
by on Nov 10, 2011 at 3:34:27 pm

Your description of it sounds a bit like it might be judder. Judder is not unique to After Effects. It's been an issue with film since its early inception. Take a look at the opening shot from Cowboys and Aliens as a recent example. It's a simple camera pan, but if you're paying attention, notice how flickery the movement is. (I noticed it in the cinema, I haven't watched it on DVD.)
This page explains a bit on how to avoid it: [link]

- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')

No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.


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Jason BaldariRe: Image flicker on x-axis 2.5D camera moves
by on Nov 10, 2011 at 7:27:51 pm

I think that's it, thanks Michael. I'm currently testing a few different options based on the info in that article. The only real bummer based on the info there is that my animation is pretty well locked at this point. If I can't find any other solution then I think the jutter will wind up remaining. Much appreciated!

Ted - Thanks for responding. I'm not rendering interlaced, but I did try the fast blur, unfortunately to no avail :/

Motion GFX & VFX
http://www.jasonbaldari.com


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ben g ungurenRe: Image flicker on x-axis 2.5D camera moves
by on Nov 11, 2011 at 8:19:20 pm

Great link Michael -- thanks for sharing it!

Ben Unguren
Motion Graphics & Editing
http://www.mostlydocumentary.com


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Tudor "Ted" JelescuRe: Image flicker on x-axis 2.5D camera moves
by on Nov 10, 2011 at 8:12:47 am

Are you rendering interlaced by chance?
Also, I found that a slight Fast Blur eliminates this issue. The amount of the blur depends on how big the images are- you'll have to test it and see how it works out.

Tudor "Ted" Jelescu
Senior VFX Artist


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Dan FredleyRe: Image flicker on x-axis 2.5D camera moves
by on Nov 10, 2011 at 9:29:55 pm

Are you using Illustrator files with clipping masks? Clipping masks have caused this kind of problem for me--I ended up just deleting the clipping masks in Illustrator and creating the masks in AE.


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Jason BaldariRe: Image flicker on x-axis 2.5D camera moves
by on Nov 10, 2011 at 11:43:27 pm

Hi Dan,

Nah, all layers are rasterized pixel PSD elements, though I know what you're talking about.

Thanks,
-Jason

Motion GFX & VFX
http://www.jasonbaldari.com


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