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I have some footage from an action camera that has been affected by vibrations. The footage seems to have an affect that looks a bit like jelly.

Is there a word for that effect and is there anything in after fx I can use to help improve it?

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Could you post a frame from your footage or if its only visible in motion post a short snippet of the footage? –  Professor Sparkles Jun 15 at 18:02

2 Answers 2

up vote 4 down vote accepted

They call this the rolling shutter effect.

Also known as the jello or wobble effect and is caused by the side to side motion of cameras that have the CMOS sensor.

The rolling shutter effect can be caused by:
fast moving objects,
moving or panning the camera quickly, or
camera vibrations.

Why does this happen?
The CMOS sensor on the camera reads information a line at a time, from top to bottom. Thus different parts of the image is recorded at DIFFERENT times, thus creating the wobble effect.

Cameras with the CCD sensor do NOT have this problem. This sensor records the whole image at once. Thus avoiding the rolling shutter effect.

There are pros and cons for using different image sensors, however it looks like we are moving to a CMOS world. This site below explains the differences between the sensors very nicely if you are curious.

http://www.bhphotovideo.com/c/find/newsLetter/Comparing-Image-Sensors.jsp

Hope that helps

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@JasonConrad My mistake. I had seen those footage under rolling shutter, but its not. Was late last night and did not think it through. –  eLouai Jul 19 at 15:40

This sounds like the end result of image stabilization on heavily moving footage. There is nothing that can really be done for it. The source of the problem is that you have motion blur on the original footage thanks to the movement of the camera.

Software can track how things are moving and adjust the position of the frame such that objects remain in constant position, but that doesn't change the fact that there is motion blur in the original frame as a result of the movement. Thus, when the objects stay still, you still see the associated motion blur moving around the objects and this is what causes that "jelly" look you described.

The best way to avoid it is to use a stabilized camera or use a higher shutter speed when recording your video to limit the motion blur incurred by a moving camera. If you still capture, say, 24 frames per second, but you capture each frame in 1/1000th of a second rather than 1/30th of a second, you end up with far less motion blur, but need far more light.

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He didn't say that the footage got stabilized in software. The effect that gets described could also be a rolling shutter effect. –  Professor Sparkles Jun 15 at 18:20
    
@ProfessorFartSparkle - true, I took that from "affected by vibrations". It's a typical action cam problem. I'm making an assumption in my answer that it was being stabilized (either in software or in camera), but it seems to fit the description a lot more than rolling shutter since that would be "slugish" rather than "vibrations". –  AJ Henderson Jun 15 at 18:23
    
I just imagine a fast ride on a motorcycle or something similar where you can get high frequency vibrations together with a rolling shutter effect when shooting from the side of the moving object. Could be a mixture of both with a result of passing objects jiggling all over the place. –  Professor Sparkles Jun 15 at 18:27
    
Hmm, good point. Either way, physical stabilization and/or faster shutter speed is still the answer though. Even with rolling shutter compounding it, the problem is lessened with reduced vibration. –  AJ Henderson Jun 15 at 18:28
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Rolling shutter is independent of shutter speed. dvinfo.net/forum/canon-eos-crop-sensor-hd/… and from dvxuser.com/jason/CMOS-CCD "Skew and other rolling shutter artifacts aren't affected by shutter speed, they're affected by the frame rate." –  Jason Conrad Jun 17 at 1:29

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