Optical Flow in Final Cut Pro X

Have you ever tried to slow down footage only to see your result is choppy or not what you were hoping for? Thankfully in Final Cut Pro X there’s a new feature called Optical Flow that gets rid of that problem.

How does Optical Flow work?

First let’s go over how exactly this neat feature works. Instead of duplicating frames or blending them together, Optical Flow creates new frames in between the current ones. This gives an extremely better-looking result!

How can I apply Optical Flow?

Retime menu in FCPX.

It is very easy to use the Optical Flow option in Final Cut X. First, select the desired clip. Now, click on the re-time icon (as seen in the picture on the right). A drop-down menu will appear giving you various options including slowing it down and speeding it up.

You will now notice a colored bar appear above your clip in the timeline. Depending on your re-timing selection it will be orange (slowed down), green (normal speed), or blue (sped up). If you were to play back the clip, it may look like what Final Cut 7 would produce. Fear not! Go back to the re-time icon and go to video quality followed by Optical Flow. Now comes the fun part: waiting! It might take a bit, but your Mac is hard at work analyzing and producing stunning results.

If you don’t like FCPX’s three timing options, just click and drag the colored bar at the top of the clip. You will now notice the percentage of the re-timed clip go up or down.

Check out FCPeffects.com‘s results in the video below.

For a more extensive tutorial, visit FCPeffects.com’s tutorial on Optical Flow.

About The Author

Connor Crosby CCMovies

I am a teenage, award-winning filmmaker and founder of Crosby Studios. I am very knowledgeable of the Final Cut Studio suite and Final Cut Pro X.

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7 Comments

Fraser August 12, 2011

I tried optical flow on a short test clip but it didn’t appear to be doing anything. The background tasks status showed something was happening for a few seconds and a “analyzing for optical flow” appeared and stayed over the clip in the viewer but nothing was going on in the background (I checked the background tasks window and everything was showing idle). Nothing seemed to have happened when I output the moivie either.
- Connor Crosby August 12, 2011
  
  Hmm that’s odd. I am not sure why that would happen. Probably one of the many bugs FCPX has.
dan August 17, 2011

same thing happened with me… it actually looks horrible. and my shutter was 1/500 when i shot it using 60P.
- Connor Crosby August 17, 2011
  
  I did as well when applying it to Ripple Training’s sample footage.
Stephan Marliss January 13, 2012

Hi all,

I use optical flow quit a bit so I thought I would speak up.

A note to FCP legacy users, you can use optical flow as well, you just have to open the clip in Motion.

I do use optical flow and frame blend (just above optical flow in the drop down menu) quite a bit. They both have their strengths and weaknesses.

Frame blend usually gets the job done and takes up far less in the way of computer resources. The effect is most affective when the shot is either static (camera on a tripod) or the shot is a slow deliberate move (camera on dolly and/or jib arm). It doesn’t do very well with jerky camera motion (handheld camera) or quick sweeping shots (bad steadicam by operators who think they know what they are doing, sorry bad experience). The same goes for the action you are shooting. It won’t work all that well with quick action.

As for optical flow. It works well, just make sure you don’t have lighting that changes drastically or else it will do strange things when processed. For those of us stuck doing events to pay the bills, that means flashes. If there is even one in the shot, forget it. During the day there is usually no issues, but there can be some little weird bits, like slight artifacts. Also, if you apply it to a clip, it will take lots of resources and it will take time. Depending on your computer, it might not even affect the clip for a awhile or even look like it was even applied (kind of like clip synching, it doesn’t show up in the library immediately for some reason). I know that when I apply it to a clip, it might not be done for an hour (and I have one of the more powerful mac pros).

Unfortunately, neither of these is perfect. By all reports, Twixtor does an amazing job, but nothing works better than shooting a higher frame rate. (Dan, try a slower shutter if possible, it will smooth things out, fast shutters tend to make things like jerky). 60 fps at 720p is not terrible, depending on the project.