Video Slow-Motion Speed & AI Optical Flow Frame Calculator (2026)

Natural slow-motion without frame dropping or interpolation is calculated as: Speed % = (Timeline FPS / Capture FPS) × 100. For example, conforming 60 FPS footage to a 24 FPS timeline yields (24 / 60) × 100 = 40% playback speed (a 2.5x slowdown).

Without optical flow interpolation, slowing 24 FPS footage to 50% forces the player to display each frame twice (12 unique frames per second), creating visible, choppy stuttering.

Optical flow algorithms analyze the velocity and vector direction of individual pixels between two consecutive frames, mathematically predicting and synthesizing brand-new intermediate frames to smooth out motion.

The 180-degree rule states that your camera shutter speed should be double your frame rate (1 / (2 × FPS)). For 24 FPS, use 1/48s or 1/50s; for 60 FPS, use 1/120s; for 120 FPS, use 1/240s to achieve natural human-like motion blur.

Use the filter: 'ffmpeg -i input.mp4 -filter:v "minterpolate='fps=60:mi_mode=mci:mc_mode=aobmc:me_mode=bidir:vsbmc=1'" output.mp4'.