Frame interpolation
Also known as: motion interpolation, frame generation, in-betweening
Creating new frames between existing ones to raise frame rate or slow motion down smoothly, using optical flow or AI models.
Updated
What it means
Frame interpolation fills the gaps between recorded frames with synthetic ones. Simple methods blend neighboring frames, which looks soft and ghosted. Better methods use optical flow to estimate motion and move pixels along it. Modern AI models predict in-between frames even more convincingly.
It has two main uses. In editing, it creates smooth slow motion from footage shot at normal frame rates. In playback, some TVs and players interpolate to higher frame rates for smoother motion, which some viewers like and others call the soap opera effect.
Interpolated frames are estimates, so their quality depends heavily on how predictable and simple the motion is.
How it works in practice
Use interpolation to stretch footage a bit further, for example turning 60 fps into a smooth quarter-speed shot, rather than turning 24 fps into extreme slow motion. Starting with more real frames always gives better results.
Dedicated tools and plugins often outperform built-in editor options, especially for complex motion. Test on a short section before processing a whole sequence, since rendering takes time. Many tools now use AI models trained on huge amounts of footage.
Check the output frame by frame around fast edges, overlapping objects and thin details, where mistakes hide best at full speed.
What to watch out for
Interpolation struggles with occlusion, when one object passes in front of another, and with repetitive patterns like spokes, fences and waves. Artifacts appear as warping, melting edges or doubled objects, and they are often worst exactly at the peak of the action.
TV interpolation can make cinematic footage look unnatural. When reviewing your own edits, turn off motion smoothing on the TV to see the real result your viewers will get.
Interpolated slow motion cannot recover sharpness lost to motion blur in the original frames. Use a fast shutter speed when recording moments you plan to slow down.
How RawClip handles it
RawClip does not generate frames. It picks and cuts the best moments from your footage as recorded. For smooth slow motion in your highlight, record key moments at 60 to 120 fps.