Avoiding Prop Flicker when Shooting Drone Video Footage

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We released a new tutorial showing how to remove prop flicker, so if you have flicker problems on drone footage, check that out. (It’s also at the bottom of this post)

But what if you want to avoid prop flicker altogether? Here’s a few tips:

But first, let’s take a look at what it is. Here’s an example video:

1- Don’t shoot in such a way that the propellers are between the sun and the camera. The reason prop flicker happens is the props are casting shadows onto the lens. If the sun is above and in front of the lens, that’s where you’ll get the shadows and the flicker. (shooting sunrise or sunset is fine because the sun is below the props)

1b- Turning the camera just slightly from the angle generating the flicker will often get rid of the flicker. You can see this in the tutorial below on removing the flicker.

2- Keep the camera pointed down slightly. It’s more likely to catch the shadows if it’s pointing straight out from the drone at 90 degrees (parallel to the props). Tilt it down a bit, 10 or 20 degrees, and that helps a lot.

3- I’ve seen lens hoods for the cameras. Sounds like they help, but I haven’t personally tried one.

Unfortunately sometimes you have to shoot something in such a way that you can’t avoid the prop flicker. In which cases using a plugin like Flicker Free allows you to eliminate or reduce the flicker problem. You can see how to deflicker videos with prop flicker in the below tutorial.

Removing Flicker from Drone Video Footage caused by Prop Flicker

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Drones are all the rage at the moment, deservedly so as some of the images and footage  being shot with them are amazing.

However, one problem that occurs is that if the drone is shooting with the camera at the right angle to the sun, shadows from the props cause flickering in the video footage. This can be a huge problem, making the video unusable. It turns out that our Flicker Free plugin is able to do a good job of removing or significantly reducing this problem. (of course, this forced us to go out and get one. Research, nothing but research!)

Here’s an example video showing exactly what prop flicker is and why it happens:

There are ways around getting the flicker in the first place: Don’t shoot into the sun, have the camera pointing down, etc. However, sometimes you’re not able to shoot with ideal conditions and you end up with flicker.

Our latest tutorial goes over how to solve the prop flicker issue with our Flicker Free plugin. The technique works in After Effects, Final Cut Pro, Avid, Resolve, etc. However the tutorial shows Flicker Free being used in Premiere Pro.

The full tutorial is below. You can even download the original flickering drone video footage and AE/Premiere project files by clicking here.

Speeding Up Flicker Free: The Order You Apply Plugins in Your Video Editing App

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One key way of speeding up the Flicker Free plugin is putting it first in the order of effects. What does this mean? Let’s say you’re using the Lumetri Color Corrector in Premiere. You want to apply Flicker Free first, then apply Lumetri. You’ll see about a 300+% speed increase vs. doing it with Lumetri first. So it looks like this:

Apply Flicker Free first in your video editing application to increase the rendering speed.

Why the Speed Difference?

Flicker Free has to analyze multiple frames to de-flicker the footage you’re using. It looks at up to 21 frames. If you have the effect applied before Flicker Free it means Lumetri is being applied TWENTY ONE times for every frame Flicker Free renders. And especially with a slow effect like Lumetri that will definitely slow everything down.

It fact, on slower machines it can bring Premiere to a grinding halt. Premiere has to render the other effect on 21 frames in order to render just one frame for Flicker Free. In this case, Flicker Free takes up a lot of memory, the other effect can take up a lot of memory and things start getting ugly fast.

Renders with Happy Endings

So to avoid this problem, just apply Flicker Free before any other effects. This goes for pretty much every video editing app. The render penalty will vary depending on the host app and what effect(s) you have applied. For example, using the Fast Color Corrector in Premiere Pro resulted in a slow down of only about 10% (vs. Lumetri and a slow down of 320%). In After Effects the slow down was about 20% with just the Synthetic Aperture color corrector that ships with AE. However, if you add more filters it can get a lot worse.

Either way, you’ll have much happier render times if you put Flicker Free first.

Hopefully this makes some sense. I’ll go into a few technical details for those that are interested. (Feel free to stop reading if it’s clear you just need to put Flicker Free first) (oh, and here are some other ways of speeding up Flicker Free)

Technical Details

With all host applications, Flicker Free, like all plugins, has to request frames through the host application API. With most plugins, like the Beauty Box Video plugin, the plugin only needs to request the current frame. You want to render frame X: Premiere Pro (or Avid, FCP, etc) has to load the frame, render any plugins and then display it. Plugins get rendered in the order you apply them. Fairly straightforward.

The Flicker Free plugin is different. It’s not JUST looking at the current frame. In order to figure out the correct luminance for each pixel (thus removing flicker) it has to look at pixels both before and after the current frame. This means it has to ask the API for up to 21 frames, analyze them, return the result to Premiere, which then finishes rendering the current frame.

So the API says, “Yes, I will do your bidding and get those 21 frames. But first, I must render them!”. And so it does. If there are no plugins applied to them, this is easy. It just hands Flicker Free the 21 original frames and goes on its merry way. If there are plugins applied, the API has to render those on each frame it gives to Flicker Free. FF has to wait around for all 21 frames to be rendered before it can render the current frame. It waits, therefore that means YOU wait. If you need a long coffee break these renders can be great. If not, they are frustrating.

If you use After Effects you may be familiar with pre-comping a layer with effects so that you can use it within a plugin applied to a different layer. This goes through a different portion of the API than when a plugin requests frames programmatically from AE. In the case of a layer in the layer pop-up the plugin just gets the original image with no effects applied. If the plugin actually asks AE for the frame one frame before it, AE has to render it.

One other thing that affects speed behind the scenes… some apps are better at caching frames that plugins ask for than other apps. After Effects does this pretty well, Premiere Pro less so. So this helps AE have faster render times when using Flicker Free and rendering sequentially. If you’re jumping around the timeline then this matters less.

Hopefully this helps you get better render times from Flicker Free. The KEY thing to remember however, is ALWAYS APPLY FLICKER FREE FIRST!

Happy Rendering!