Why Frame Rate Mismatch Happens in Final Cut Pro

Direct methods for fixing stuttering playback, optical flow, and incorrect project frame rates.

The best way to fix why frame rate mismatch happens in Final Cut Pro is to ensure your project's frame rate matches your primary camera, convert mixed frame rate footage with optical flow, and use automatic speed settings for slow motion.

Here are the direct methods to fix why frame rate mismatch happens in Final Cut Pro.

What is the fastest way to fix incorrect project frame rates?

If your 60fps drone footage looks incredibly choppy or drops frames when played back in the timeline, Final Cut Pro automatically set the project frame rate to the first clip you dragged in (which might have been a 24fps smartphone clip), forcing the software to mechanically delete 36 frames every second.

To quickly fix incorrect project frame rates:

Select your active Project (timeline) in the Browser sidebar (top left).
Open the Inspector panel (top right) and click the Modify button under the Project Properties section.
In the dialog box, uncheck Use Automatic Settings (if visible) and select Custom.
Locate the Video section and click the Rate dropdown menu.
Change the frame rate from 24p or 30p to the exact frame rate of your primary footage (e.g., 60p).
Click OK. Final Cut Pro will instantly rebuild the timeline at 60 frames per second, allowing your drone footage to play perfectly smoothly without dropping a single frame.

How do you convert mixed frame rate footage?

If you have a 30fps clip inside a 24fps timeline and the playback stutters rhythmically every single second, Final Cut Pro is simply deleting 6 frames out of the 30 to make it fit into 24 slots.

To convert mixed frame rate footage:

Select the stuttering 30fps clip on your 24fps timeline.
Open the Video Inspector panel (the filmstrip icon) on the top right.
Scroll down to the Rate Conform section at the very bottom.
Click the dropdown menu for Frame Sampling and change it from "Floor" or "Nearest" to Optical Flow.
Press Control-R to manually render the clip. Final Cut Pro will use advanced Apple Silicon AI to intelligently blend and morph the 30fps clip into 24fps, creating completely new frames to eliminate the stuttering playback.

How do you apply perfect automatic slow motion?

If you shot a video at 120fps but it plays back at normal speed (with audio) on your 24fps timeline, Final Cut Pro is dropping 96 frames a second instead of playing it back in buttery smooth slow motion.

To apply perfect automatic slow motion:

Drag the 120fps clip onto your 24fps timeline.
Select the clip on the timeline.
Go to the top menu bar and click the Retime menu (the speedometer icon below the viewer window) or click the small arrow next to the speed percentage on the clip.
Select Automatic Speed.
Final Cut Pro will instantly stretch the clip to play every single frame exactly once, creating perfect 20% slow motion without dropping or interpolating a single frame.