einundzwanzig-verein/videos/.opencode/skills/remotion-best-practices/rules/timing.md

name, description, metadata

name	description	metadata
timing	Interpolation curves in Remotion - linear, easing, spring animations	tags spring, bounce, easing, interpolation

A simple linear interpolation is done using the interpolate function.

import {interpolate} from 'remotion';

const opacity = interpolate(frame, [0, 100], [0, 1]);

By default, the values are not clamped, so the value can go outside the range [0, 1].
Here is how they can be clamped:

const opacity = interpolate(frame, [0, 100], [0, 1], {
  extrapolateRight: 'clamp',
  extrapolateLeft: 'clamp',
});

Spring animations

Spring animations have a more natural motion.
They go from 0 to 1 over time.

import {spring, useCurrentFrame, useVideoConfig} from 'remotion';

const frame = useCurrentFrame();
const {fps} = useVideoConfig();

const scale = spring({
  frame,
  fps,
});

Physical properties

The default configuration is: mass: 1, damping: 10, stiffness: 100.
This leads to the animation having a bit of bounce before it settles.

The config can be overwritten like this:

const scale = spring({
  frame,
  fps,
  config: {damping: 200},
});

The recommended configuration for a natural motion without a bounce is: { damping: 200 }.

Here are some common configurations:

const smooth = {damping: 200}; // Smooth, no bounce (subtle reveals)
const snappy = {damping: 20, stiffness: 200}; // Snappy, minimal bounce (UI elements)
const bouncy = {damping: 8}; // Bouncy entrance (playful animations)
const heavy = {damping: 15, stiffness: 80, mass: 2}; // Heavy, slow, small bounce

Delay

The animation starts immediately by default.
Use the delay parameter to delay the animation by a number of frames.

const entrance = spring({
  frame: frame - ENTRANCE_DELAY,
  fps,
  delay: 20,
});

Duration

A spring() has a natural duration based on the physical properties.
To stretch the animation to a specific duration, use the durationInFrames parameter.

const spring = spring({
  frame,
  fps,
  durationInFrames: 40,
});

Combining spring() with interpolate()

Map spring output (0-1) to custom ranges:

const springProgress = spring({
  frame,
  fps,
});

// Map to rotation
const rotation = interpolate(springProgress, [0, 1], [0, 360]);

<div style={{rotate: rotation + 'deg'}} />;

Adding springs

Springs return just numbers, so math can be performed:

const frame = useCurrentFrame();
const {fps, durationInFrames} = useVideoConfig();

const inAnimation = spring({
  frame,
  fps,
});
const outAnimation = spring({
  frame,
  fps,
  durationInFrames: 1 * fps,
  delay: durationInFrames - 1 * fps,
});

const scale = inAnimation - outAnimation;

Easing

Easing can be added to the interpolate function:

import {interpolate, Easing} from 'remotion';

const value1 = interpolate(frame, [0, 100], [0, 1], {
  easing: Easing.inOut(Easing.quad),
  extrapolateLeft: 'clamp',
  extrapolateRight: 'clamp',
});

The default easing is Easing.linear.
There are various other convexities:

• Easing.in for starting slow and accelerating
• Easing.out for starting fast and slowing down
• Easing.inOut

and curves (sorted from most linear to most curved):

• Easing.quad
• Easing.sin
• Easing.exp
• Easing.circle

Convexities and curves need be combined for an easing function:

const value1 = interpolate(frame, [0, 100], [0, 1], {
  easing: Easing.inOut(Easing.quad),
  extrapolateLeft: 'clamp',
  extrapolateRight: 'clamp',
});

Cubic bezier curves are also supported:

const value1 = interpolate(frame, [0, 100], [0, 1], {
  easing: Easing.bezier(0.8, 0.22, 0.96, 0.65),
  extrapolateLeft: 'clamp',
  extrapolateRight: 'clamp',
});