Additionally, Flicker Free’s settings can affect render times. For example, a Time Radius that’s larger will make for a longer render time. If you have Time Radius set to 10, Flicker Free is asking the host app to render 21 frames at once (the current frame, 10 before, 10 after) when processing a single frame. It then has to analyze all the color information in those frames.

New Flicker Free 2.0 settings: Motion compensation and detect motion can both result in slow performance and longer renders. You will have to play around with the two settings because even if they are causing FF to be slow, those may be the settings you need to fix your clip.

If you're using a high resolution image sequence it will be slower because Flicker Free is analyzing more pixels than it would for HD footage. It shouldn't be THAT much slower, so if you’re experiencing an extreme slow down please email us at sales@digitalanarchy.com

To ensure your Flicker Free renders are optimized, you need to have your GPU is on/enabled. Go to (Mac: Macintosh HD>Users>Shared>Digital Anarchy, Windows: Users>Public>Public Documents>Digital Anarchy) and in this folder location you will find either a DA_CUDA_Device.txt, DA_Metal_Devices.txt, DA_OpenCL_Devices.txt file. Open the devices file and change everything that says "Enabled=Off" to "Enabled=On.” Once you’ve changed that, save the file and restart your video editing application. Now, the next time you render, you should see improvements.

If you are using Premiere, AME, or After Effects, you will also need to make sure you set your mercury renderer correctly for optimization. Set the mercury renderer in these applications to OpenCL, Metal, or CUDA. Not all of these options will be available. The options you will see are based on the graphics card you have in your computer.

For instance, if you have Time Radius set to 10, Flicker Free is asking the host app to render 21 frames at once (the current frame, 10 before, 10 after) when processing a single frame. It then has to analyze all the color information in those frames.

Especially with 4K or larger, it can take a minute or two to render a frame. If background rendering is on or scrubbing is active, FCP will start trying to request all those frames for multiple frames at once. This can bring FCP to a crawl or even crash it. Move to a point on the timeline, let it render, then make adjustments. Clicking around the timeline without letting the current frame render will just slow things down even more.

Dropping the 4K sequence into a 1080p timeline doesn't make a difference in render speed. It still has to access the 4K source file. However, rendering a 4K file out to a 1080p file and then re-importing it WILL make a difference. Now, FCP will just be dealing with HD frames and it makes a huge difference. If your final delivery is to 1080p or 720p, consider rendering out an intermediary file at that resolution. It'll work much faster.

You should apply Flicker Free BEFORE applying other effects. If you apply it afterwards, the host app or graphics card may run out of memory trying to render all those frames and won’t render. In which case, you’ll get a render error, black frames, or some other odd behavior.

If you are getting black frames without other effects involved, this may be a CPU render issue that affects playback. Make sure that the effect is using GPU and not CPU. To see if it is only affecting playback, you can test it by exporting the clip and check if the black frames appear on the export. Another reason for render errors are outdated graphics drivers. Update your graphics driver and check to see if your issue still persists. If you are still running into the issue, contact sales@digitalanarchy.com.

Reducing the Time Radius will help significantly, as the main problem is that FF is trying to blend too many frames that vary a lot. Also, try adjusting the Threshold to a lower value. That’s really all you can do. Of course, it may not be that big of a deal. Play it back in real time and see how it looks. Frequently the problem is only noticeable when you turn Flicker Free on and off in the host application since you’re looking for a difference. When played back normally much of the time it’s not noticeable by the viewer.

For low contrast areas, Shading can also happen, but it looks more like a blur. For example, if someone moves their head very quickly, you may see some softness in areas like the eyes.

Ghosting: This is kind of rare but happens when you’ve got fast moving objects. Again, it’s more of an issue with high contrast areas of the scene (e.g. a bright tennis ball moving across a black background). The object will appear in a frame with ‘ghosts’ or ‘echoes’ of itself at the positions it was at in prior frames. Reducing the Time Radius can help with this. Also try adjusting the Threshold to a lower value.

Often, the render can be dramatically increased when video effects are applied to a clip before Flicker Free does its flicker correction. The host app and type of filter will change the degree to which the render time will be increased. You can avoid this altogether by making sure Flicker Free is applied in your effect chain before any other filters that might change the way your footage appears.

Sometimes you may find it best to do an export of the clip that needs to use Flicker Free first and then reimport the correct clip back into the timeline. Then, you can apply the video effects onto the corrected clip and won’t have to worry about other effects conflicting with Flicker Free and running into potential errors.

If you intend to use 4K footage in your renders we suggest trying the demo first to ensure your GPU is compatible. Please also see Resolve recommendations for GPU.