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jerky output problem. related to framerate or camera settings?

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Marc Nibor
jerky output problem. related to framerate or camera settings?
on Jul 1, 2015 at 4:39:46 pm

Got a problem, with jerky render results. Example file is attached:
9010_example.mp4.zip

The problem is most obvious when you take a look at the third blue line... when it gets close to the camera it looks all jerky.
In a 3D app I could probably fix this by using a slower shutter speed but amaik there is nothing like this in AE?

In my AE file the camera is moving from left to right. The panels with the blue lines are all static.
Motion Blur is turned on for/on all layers.

The problem gets better when using a higher framerate.
Right now I use 25 fps and I need to stick to it!

Does anyone know how to make this look smoother?



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Dave LaRonde
Re: jerky output problem. related to framerate or camera settings?
on Jul 1, 2015 at 4:46:50 pm
Last Edited By Dave LaRonde on Jul 1, 2015 at 5:27:52 pm

Welcome to the world of judder, a phenomenon that occurs more frequently at slower frame rates like yours and is most visible in horizontal motion.

If you're stuck at 25 fps, you can change the shutter angle from its default 180-degree opening to something not possible in the real world, like 720-degrees. See if it helps.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Marc Nibor
Re: jerky output problem. related to framerate or camera settings?
on Jul 2, 2015 at 10:43:07 am

Thank you Dave. I was actually hoping for a suggestion similar to yours...
Unfortunately the result is still not usable. The judder is still clearly visible - except that everything is more blurry.
I tried many settings.

Maybe there's a workaround to fix this.
I need this AE clip for later use in a Premiere Project which needs to be 25fps. I tried to render the AE clip with 50 fps and the problem is barely noticable. But I'm afraid that if I render the 50fps file in my 25 fps premiere project that everything looks the same again.
So I gave it a quick try... It looks a bit different now I guess.
But before I spend all day with trial and error I hope someone can give me a suggestion what is best practice in this case.
Does "frame blend" help in a situation like this?



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Dave LaRonde
Re: jerky output problem. related to framerate or camera settings?
on Jul 2, 2015 at 3:16:33 pm

The only sure way to eliminate the problem is to change the speed of the movement. Should it be faster? Slower? That's up to you.

This isn't a problem unique to AE, either. It has existed since they first started shooting film. DPs have jealously guarded their solutions for decades. It's such knowledge, gained by years of experience, that keeps them employed... and you don't give away trade secrets.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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