Flicker Free – Effective Flicker Removal Plugin

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by Tim FokMay 9^th, 2014

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Digital Anarchy has developed a plugin called Flicker Free. Working with FCP, Premiere Pro and After Effects (among others) it very effectively removes flicker from time lapses, slow motion and refresh rate phasing (LED lighting and monitor screens).

Time-lapse is a widely used filmmaking technique. It was first made popular during the video DSLR movement and since then a multitude of accessories and software support to improve the workflow has been developed. One aspect of these is flicker reduction software, smoothing out exposure shifts over a long period of time.

I’ve used a few selections that have been great at this process. Similar problems are present in other genres of filmmaking. As these become more popular, many are encountering new forms of flicker on a regular basis. Slow motion and LED lighting have become repeated offenders, as they become more accessible and cost-effective. However, these are different forms of flicker to the kind we often find related with time-lapse.

LED and monitor screen flicker modulate and band. Slow motion can also, stem from light sources and can be a lot more prominent than exposure shifts within time lapses. For these reasons, the same flicker reduction tools have not always been effective. Where these time lapse-specific flicker reduction tools fall short, is where Flicker Free steps in.

Philip Bloom made a tutorial on a DIY method for slow-motion flicker removal. This is only effective with certain types of slow-motion flicker, where the conflicting light source is strictly on/off (no modulating). Opacity blending frames can also create a kind of motion blur, so the technique is not always effective.

Back onto Flicker Free. The software works by analyzing frames within your image, and how the luminance and brightness values relate with neighboring frames. It then looks to smooth out these changes by adding light exposure alterations.

The plugin by Digital Anarchy is quick and simple to use, working seamlessly with your parent NLE system. It contains a few presets including time-lapse, slow-mo and a few different types of LED lights and monitor screens. It then has a few parameters including sensitivity, threshold, time radius, and ability to analyze channels independently/together. I strongly recommend checking out the instruction manual found here for explanations of how each parameter affects your outcome.

The test footage online is a little hard to determine due to the low-quality output, so I put it to some test of my own. Below is a quick example timeline of a few conflicting clips I’ve found in my own archives (some 4 years old!). Pay particular attention to the modulating flicker resolution of clip 2, this is really where this plugin shines as modulating flicker is hard to remove.

It doesn’t remove all of it as you can see, but it does a pretty decent job for most of it. In regards to the last clip, I thought I’d add three examples – original, preset applied, and preset tweaked. This just gives you an idea of what it looks like in comparison to applying one of the untouched presets, and after you have adjusted the parameters to suit your clip.

It’s clear that in some cases you have to tweak the settings to get it just right. For reference, 90% of the other clips were just a preset. There was some flicker I wasn’t able to come close to removing in another clip (frame grab below), caused by my Ice Light. However this modulation was more of a band than a flicker, and I anticipated it would be a little too much for the plugin as the luminance values are very similar throughout the whole clip.

Digital Anarchy states that the larger the bands usually the more effective the plugin will be.

There are quite a few plugins out there that can resolve similar results. However, these are usually tied up in expensive software packages. Flicker Free is simply a nice cost-effective third-party plugin for an NLE system of your choice. Whilst it shouldn’t be relied on as a fundamental part to any workflow, it certainly does well at getting you out of some otherwise awkward situations.

via Philip Bloom