Strobe Effect - Repeat Frames Bug

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Level 1

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Strobe Effect - Repeat Frames Bug

I'm trying to add a strobe/posterize effect to my animations in FCPX but it spazzes out when I add it. It's a simple plugin using the strobe effect from Motion to give that stop motion feel. I've downloaded essentially the same plugin from two different creators and they all have the same issue. I've tried adding it to each shape and title individually, adding it as an adjustment layer above all of them, creating compound clips, etc. I even exported the animation without the effect and then brought it back into FCPX to see if that would work, but no luck. Resetting preferences didn't help either.

I went ahead and tested the plugin on a few different video clips, all different frame rates, and it seems to work fine for those. I've noticed this jitter/repeat frame issue in the past with certain wipe transitions or keyframe animations and I was never able to resolve it then either.

I'm stumped.

Here is a snippet of the animation without the effect:

https://www.dropbox.com/s/w8v3xj1tkcaz0mv/test%20animation.mp4?dl=0

Here is a snippet of the animation with the effect added:

https://www.dropbox.com/s/sleacg66lhrb320/test%20animation%20-%20strobe.mp4?dl=0

MacBook Pro 16″

Posted on May 23, 2023 9:22 PM

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Answer 1

fox_m

Level 6

12,583 points

May 24, 2023 10:37 AM in response to nickvinny

Your sample video is an animated graphic, which shouldn't make any difference.

Taking a look, frame by frame of the sample, there are several sections where the elements "jump" a significant distance from one frame to the next, then back again on the next frame.

Strobe relies on floating point calculations which are applied to *discreet* frames (integer values). Certain settings are going to create rounding "errors". For example, even in a regular video clip, if you go frame by frame and count the number of frames that don't change, for certain settings, this is going to be variable, e.g., 7 still frames in one set then 8 still frames in the next.

Every once in awhile, going frame by frame, you may notice that the image will change, then on the next frame it... like... resets... to the frame before.

At full speed playback, in a regular video "image sequence" you probably wouldn't notice this behavior — but in the animated graphic... it will just look twisted.

THIS effect which I just called Fake Strobe (download it here: https://fcpxtemplates.com/?sdm_process_download=1&download_id=26554), holds an integer amount of frames before advancing... but the parameter is going to be a little strange.

At 0, the playback is 1 frame per second (shows 1 frame - HOLDS the rest - then skips to 1 + Frame Rate frames... approximately — I'm not making any guarantees about fractional frame rates.) At 50(%), you'll get 2 frames per second. At 75% - 3fps (I think)... but you get the point. The scale is logarithmic. At 100% - full speed playback.

Install in Effects / category of your choice.

Won't hurt to give it a shot. HTH

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Strobe Effect - Repeat Frames Bug

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