How do I convert 60fps video to 30fps?

Drop every second frame: set output to 30fps and the converter discards half the frames evenly. Motion stays smooth because 60 divides cleanly into 30. This halves motion data (not file size exactly — bitrate decides that) and matches standard timelines and platforms.

How do I make smooth slow motion from 60fps footage?

Interpret the 60fps footage at a slower timeline rate instead of re-encoding: 60fps played at 30fps is perfect 2× slow motion with every frame real. For even slower results, motion interpolation synthesizes in-between frames — smoother, but slower to process and occasionally artifact-prone on fast chaotic motion.

What is motion interpolation in frame rate conversion?

Instead of duplicating frames when raising FPS (30→60 by doubling each frame), interpolation analyzes motion between frames and synthesizes genuinely new in-between frames. Results look far smoother, but processing takes much longer, stresses the CPU, and can warp fast unpredictable motion — use it for clean footage, not confetti.

Does lowering FPS reduce file size?

Modestly, not proportionally: half the frames doesn't mean half the file, because each remaining frame gets more bitrate at fixed quality settings. The real size wins come from resolution and codec choices. Lower FPS mainly serves compatibility (24fps timelines) and slow-motion workflows.

How do I speed up a video into a timelapse?

Raise playback speed (2×–8×) rather than changing FPS: dropping frames evenly at higher speed multipliers keeps motion coherent. For hour-long captures, combine speed-up with downscaling — timelapses don't need 4K to look spectacular.

Can I batch convert frame rates across a folder?

Yes — set the target FPS once (e.g. everything to 30fps for a uniform timeline) and run the folder, with per-file status for the odd variable-frame-rate phone clip that needs attention. Preview one file's frames before committing the batch.

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Change Video FPS: Slow Down, Speed Up & Convert Frame Rates in Batch

Lowering FPS drops frames (easy). Raising FPS invents them (hard). Slow motion, timelapses, and delivery matching — when to drop, when to interpolate, and how to preview frames before you commit.

By Hadi Karaki, maker of FormatifSeptember 16, 202610 min read

The one truth: down is easy, up is invented

Lowering FPS (60→30→24) discards frames evenly — fast, safe, quality-neutral. Raising FPS (30→60) must create frames from nothing: naive mode duplicates each frame (juddery), motion interpolation synthesizes genuinely new in-between frames by analyzing movement (smooth, but slow, CPU-heavy, and occasionally warpy on chaotic motion). Every task below is one of these two directions — knowing which decides everything.

Task	Direction	Use
60fps → 30/24fps delivery	Down (drop)	Match timelines, halve motion data
Slow motion from 60fps	Interpret slower	2× at 30fps, ~2.5× at 24fps — all real frames
30fps → 60fps smoothing	Up (interpolate)	Motion interpolation ON; verify on your footage
Timelapse speed-up	Speed multiplier	2–8× playback; combine with downscale

Which frame rate to target in the first place? Our frame rates guide covers 24 vs 30 vs 60 vs 120.

One caveat before you convert: phone and screen-recorder footage is usually variable frame rate, which breaks audio sync in editors regardless of your target FPS. Our VFR to CFR guide fixes the clock first.

Preview frames before you commit (single mode)

The expensive mistake is converting blind: interpolation artifacts only show at full motion, and wrong FPS choices surface in editing. Scrub the FPS slider (1–60) and watch the canvas preview update frame by frame — toggle motion interpolation on to judge smoothness versus processing cost before the batch runs. Five minutes of previewing saves hours of re-encoding.

Single mode: scrubbing the 1–60 FPS slider with live frame preview and the motion interpolation toggle.

Same job in FFmpeg (fps filter)

ffmpeg -i in.mp4 -vf "fps=30" -c:v libx264 -crf 20 -c:a copy out.mp4

Quick Solution

Preview one, convert the folder.

Dial the FPS in single mode with live preview, flip on interpolation only if the footage earns it — then run the identical settings across the folder. Formatif Pro ($8.95 one-time) pairs single-file frame preview with folder batch offline, so mixed 24/30/60fps shoots leave standardized — with per-file status on the odd variable-frame-rate phone clip.

Download free trial

Frame rate questions, answered

60fps to 30fps how?

Drop every second frame — clean 2:1 division, smooth result. Halves motion data; bitrate decides file size.

Smooth slow motion from 60fps?

Interpret at 30fps (2×, all real frames). Slower needs interpolation — smoother but CPU-heavy, check chaotic motion.

What is motion interpolation?

Synthesized in-between frames from motion analysis vs naive duplication. Smoother, slower, occasionally warpy.

Lower FPS = smaller files?

Modestly, not proportionally. FPS serves compatibility and slow-mo; resolution/codec drive size.

Timelapse speed-up?

2–8× playback speed, plus downscale. Timelapses don't need 4K to look spectacular.

Batch convert frame rates?

One target FPS for the folder, preview first, per-file status for VFR phone clips.

Keep learning

Frame rates explained

24 vs 30 vs 60 vs 120 — which to target before converting.

OBS recording settings

Record at the right FPS first — CQP, format, audio.

Compress video: 4 methods

Encode converted frame rates sensibly for delivery.

Every frame rate, one folder, one run.

Formatif Pro ($8.95 one-time) and Formatif AI ($12.95 one-time) handle video, image, and audio conversion offline — with batch workflows, no file size limits, and a 3-day free trial.

Download free trial Read: frame rates guide

FFmpeg fps filters do this free per file — preview plus batch removes the guesswork at folder scale.

Written by

Hadi KarakiLinkedIn

Founder of Formatif, a local-first offline media processing suite for Windows and Linux. Hadi writes about video, image, and audio formats, compression, and privacy-first desktop workflows.