Remotion Best Practices

When to use

Use this skills whenever you are dealing with Remotion code to obtain the domain-specific knowledge.

New project setup

When in an empty folder or workspace with no existing Remotion project, scaffold one using:

npx create-video@latest --yes --blank --no-tailwind my-video

Replace my-video with a suitable project name.

Starting preview

Stsrt the Remotion Studio to preview a video:

npx remotion studio

Optional: one-frame render check

You can render a single frame with the CLI to sanity-check layout, colors, or timing. Skip it for trivial edits, pure refactors, or when you already have enough confidence from Studio or prior renders.

npx remotion still [composition-id] --scale=0.25 --frame=30

At 30 fps, --frame=30 is the one-second mark (--frame is zero-based).

Captions

When dealing with captions or subtitles, load the ./rules/subtitles.md file for more information.

Using FFmpeg

For some video operations, such as trimming videos or detecting silence, FFmpeg should be used. Load the ./rules/ffmpeg.md file for more information.

Silence detection

When needing to detect and trim silent segments from video or audio files, load the ./rules/silence-detection.md file.

Audio visualization

When needing to visualize audio (spectrum bars, waveforms, bass-reactive effects), load the ./rules/audio-visualization.md file for more information.

Sound effects

When needing to use sound effects, load the ./rules/sfx.md file for more information.

How to use

Read individual rule files for detailed explanations and code examples:

• rules/3d.md - 3D content in Remotion using Three.js and React Three Fiber
• rules/animations.md - Fundamental animation skills for Remotion
• rules/assets.md - Importing images, videos, audio, and fonts into Remotion
• rules/audio.md - Using audio and sound in Remotion - importing, trimming, volume, speed, pitch
• rules/calculate-metadata.md - Dynamically set composition duration, dimensions, and props
• rules/can-decode.md - Check if a video can be decoded by the browser using Mediabunny
• rules/charts.md - Chart and data visualization patterns for Remotion (bar, pie, line, stock charts)
• rules/compositions.md - Defining compositions, stills, folders, default props and dynamic metadata
• rules/extract-frames.md - Extract frames from videos at specific timestamps using Mediabunny
• rules/fonts.md - Loading Google Fonts and local fonts in Remotion
• rules/get-audio-duration.md - Getting the duration of an audio file in seconds with Mediabunny
• rules/get-video-dimensions.md - Getting the width and height of a video file with Mediabunny
• rules/get-video-duration.md - Getting the duration of a video file in seconds with Mediabunny
• rules/gifs.md - Displaying GIFs synchronized with Remotion's timeline
• rules/images.md - Embedding images in Remotion using the Img component
• rules/light-leaks.md - Light leak overlay effects using @remotion/light-leaks
• rules/lottie.md - Embedding Lottie animations in Remotion
• rules/measuring-dom-nodes.md - Measuring DOM element dimensions in Remotion
• rules/measuring-text.md - Measuring text dimensions, fitting text to containers, and checking overflow
• rules/sequencing.md - Sequencing patterns for Remotion - delay, trim, limit duration of items
• rules/tailwind.md - Using TailwindCSS in Remotion
• rules/text-animations.md - Typography and text animation patterns for Remotion
• rules/timing.md - Timing with interpolate and Bézier easing, springs
• rules/transitions.md - Scene transition patterns for Remotion
• rules/transparent-videos.md - Rendering out a video with transparency
• rules/trimming.md - Trimming patterns for Remotion - cut the beginning or end of animations
• rules/videos.md - Embedding videos in Remotion - trimming, volume, speed, looping, pitch
• rules/parameters.md - Make a video parametrizable by adding a Zod schema
• rules/maps.md - Add a map using Mapbox and animate it
• rules/silence-detection.md - Adaptive silence detection using FFmpeg loudnorm and silencedetect
• rules/voiceover.md - Adding AI-generated voiceover to Remotion compositions using ElevenLabs TTS

Using Three.js and React Three Fiber in Remotion

Follow React Three Fiber and Three.js best practices. Only the following Remotion-specific rules need to be followed:

Prerequisites

First, the @remotion/three package needs to be installed. If it is not, use the following command:

npx remotion add @remotion/three # If project uses npm
bunx remotion add @remotion/three # If project uses bun
yarn remotion add @remotion/three # If project uses yarn
pnpm exec remotion add @remotion/three # If project uses pnpm

Using ThreeCanvas

You MUST wrap 3D content in <ThreeCanvas> and include proper lighting. <ThreeCanvas> MUST have a width and height prop.

import { ThreeCanvas } from "@remotion/three";
import { useVideoConfig } from "remotion";

const { width, height } = useVideoConfig();

<ThreeCanvas width={width} height={height}>
  <ambientLight intensity={0.4} />
  <directionalLight position={[5, 5, 5]} intensity={0.8} />
  <mesh>
    <sphereGeometry args={[1, 32, 32]} />
    <meshStandardMaterial color="red" />
  </mesh>
</ThreeCanvas>;

No animations not driven by useCurrentFrame()

Shaders, models etc MUST NOT animate by themselves. No animations are allowed unless they are driven by useCurrentFrame(). Otherwise, it will cause flickering during rendering.

Using useFrame() from @react-three/fiber is forbidden.

Animate using useCurrentFrame()

Use useCurrentFrame() to perform animations.

const frame = useCurrentFrame();
const rotationY = frame * 0.02;

<mesh rotation={[0, rotationY, 0]}>
  <boxGeometry args={[2, 2, 2]} />
  <meshStandardMaterial color="#4a9eff" />
</mesh>;

Using <Sequence> inside <ThreeCanvas>

The layout prop of any <Sequence> inside a <ThreeCanvas> must be set to none.

import { Sequence } from "remotion";
import { ThreeCanvas } from "@remotion/three";

const { width, height } = useVideoConfig();

<ThreeCanvas width={width} height={height}>
  <Sequence layout="none">
    <mesh>
      <boxGeometry args={[2, 2, 2]} />
      <meshStandardMaterial color="#4a9eff" />
    </mesh>
  </Sequence>
</ThreeCanvas>;

All animations MUST be driven by the useCurrentFrame() hook. Write animations in seconds and multiply them by the fps value from useVideoConfig().

For eased motion, prefer interpolate with explicit frame ranges and an easing—especially Easing.bezier, which matches CSS cubic-bezier so timing can be shared with web specs and curve editors. See timing.

import { useCurrentFrame, Easing } from "remotion";

export const FadeIn = () => {
  const frame = useCurrentFrame();
  const { fps } = useVideoConfig();

  const opacity = interpolate(frame, [0, 2 * fps], [0, 1], {
    extrapolateRight: "clamp",
    extrapolateLeft: "clamp",
    easing: Easing.bezier(0.16, 1, 0.3, 1),
  });

  return <div style={{ opacity }}>Hello World!</div>;
};

CSS transitions or animations are FORBIDDEN - they will not render correctly. Tailwind animation class names are FORBIDDEN - they will not render correctly.

Importing assets in Remotion

The public folder

Place assets in the public/ folder at your project root.

Using staticFile()

You MUST use staticFile() to reference files from the public/ folder:

import { Img, staticFile } from "remotion";

export const MyComposition = () => {
  return <Img src={staticFile("logo.png")} />;
};

The function returns an encoded URL that works correctly when deploying to subdirectories.

Using with components

Images:

import { Img, staticFile } from "remotion";

<Img src={staticFile("photo.png")} />;

Videos:

import { Video } from "@remotion/media";
import { staticFile } from "remotion";

<Video src={staticFile("clip.mp4")} />;

Audio:

import { Audio } from "@remotion/media";
import { staticFile } from "remotion";

<Audio src={staticFile("music.mp3")} />;

Fonts:

import { staticFile } from "remotion";

const fontFamily = new FontFace("MyFont", `url(${staticFile("font.woff2")})`);
await fontFamily.load();
document.fonts.add(fontFamily);

Remote URLs

Remote URLs can be used directly without staticFile():

<Img src="https://example.com/image.png" />
<Video src="https://remotion.media/video.mp4" />

Important notes

• Remotion components (<Img>, <Video>, <Audio>) ensure assets are fully loaded before rendering
• Special characters in filenames (#, ?, &) are automatically encoded

Audio Visualization in Remotion

Prerequisites

npx remotion add @remotion/media-utils

Loading Audio Data

Use useWindowedAudioData() (https://www.remotion.dev/docs/use-windowed-audio-data) to load audio data:

import { useWindowedAudioData } from "@remotion/media-utils";
import { staticFile, useCurrentFrame, useVideoConfig } from "remotion";

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

const { audioData, dataOffsetInSeconds } = useWindowedAudioData({
  src: staticFile("podcast.wav"),
  frame,
  fps,
  windowInSeconds: 30,
});

Spectrum Bar Visualization

Use visualizeAudio() (https://www.remotion.dev/docs/visualize-audio) to get frequency data for bar charts:

import { useWindowedAudioData, visualizeAudio } from "@remotion/media-utils";
import { staticFile, useCurrentFrame, useVideoConfig } from "remotion";

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

const { audioData, dataOffsetInSeconds } = useWindowedAudioData({
  src: staticFile("music.mp3"),
  frame,
  fps,
  windowInSeconds: 30,
});

if (!audioData) {
  return null;
}

const frequencies = visualizeAudio({
  fps,
  frame,
  audioData,
  numberOfSamples: 256,
  optimizeFor: "speed",
  dataOffsetInSeconds,
});

return (
  <div style={{ display: "flex", alignItems: "flex-end", height: 200 }}>
    {frequencies.map((v, i) => (
      <div
        key={i}
        style={{
          flex: 1,
          height: `${v * 100}%`,
          backgroundColor: "#0b84f3",
          margin: "0 1px",
        }}
      />
    ))}
  </div>
);

• numberOfSamples must be power of 2 (32, 64, 128, 256, 512, 1024)
• Values range 0-1; left of array = bass, right = highs
• Use optimizeFor: "speed" for Lambda or high sample counts

Important: When passing audioData to child components, also pass the frame from the parent. Do not call useCurrentFrame() in each child - this causes discontinuous visualization when children are inside <Sequence> with offsets.

Waveform Visualization

Use visualizeAudioWaveform() (https://www.remotion.dev/docs/media-utils/visualize-audio-waveform) with createSmoothSvgPath() (https://www.remotion.dev/docs/media-utils/create-smooth-svg-path) for oscilloscope-style displays:

import {
  createSmoothSvgPath,
  useWindowedAudioData,
  visualizeAudioWaveform,
} from "@remotion/media-utils";
import { staticFile, useCurrentFrame, useVideoConfig } from "remotion";

const frame = useCurrentFrame();
const { width, fps } = useVideoConfig();
const HEIGHT = 200;

const { audioData, dataOffsetInSeconds } = useWindowedAudioData({
  src: staticFile("voice.wav"),
  frame,
  fps,
  windowInSeconds: 30,
});

if (!audioData) {
  return null;
}

const waveform = visualizeAudioWaveform({
  fps,
  frame,
  audioData,
  numberOfSamples: 256,
  windowInSeconds: 0.5,
  dataOffsetInSeconds,
});

const path = createSmoothSvgPath({
  points: waveform.map((y, i) => ({
    x: (i / (waveform.length - 1)) * width,
    y: HEIGHT / 2 + (y * HEIGHT) / 2,
  })),
});

return (
  <svg width={width} height={HEIGHT}>
    <path d={path} fill="none" stroke="#0b84f3" strokeWidth={2} />
  </svg>
);

Bass-Reactive Effects

Extract low frequencies for beat-reactive animations:

const frequencies = visualizeAudio({
  fps,
  frame,
  audioData,
  numberOfSamples: 128,
  optimizeFor: "speed",
  dataOffsetInSeconds,
});

const lowFrequencies = frequencies.slice(0, 32);
const bassIntensity =
  lowFrequencies.reduce((sum, v) => sum + v, 0) / lowFrequencies.length;

const scale = 1 + bassIntensity * 0.5;
const opacity = Math.min(0.6, bassIntensity * 0.8);

Volume-Based Waveform

Use getWaveformPortion() (https://www.remotion.dev/docs/get-waveform-portion) when you need simplified volume data instead of frequency spectrum:

import { getWaveformPortion } from "@remotion/media-utils";
import { useCurrentFrame, useVideoConfig } from "remotion";

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

const waveform = getWaveformPortion({
  audioData,
  startTimeInSeconds: currentTimeInSeconds,
  durationInSeconds: 5,
  numberOfSamples: 50,
});

// Returns array of { index, amplitude } objects (amplitude: 0-1)
waveform.map((bar) => (
  <div key={bar.index} style={{ height: bar.amplitude * 100 }} />
));

Postprocessing

Low frequencies naturally dominate. Apply logarithmic scaling for visual balance:

const minDb = -100;
const maxDb = -30;

const scaled = frequencies.map((value) => {
  const db = 20 * Math.log10(value);
  return (db - minDb) / (maxDb - minDb);
});

Using audio in Remotion

Prerequisites

First, the @remotion/media package needs to be installed. If it is not installed, use the following command:

npx remotion add @remotion/media

Importing Audio

Use <Audio> from @remotion/media to add audio to your composition.

import { Audio } from "@remotion/media";
import { staticFile } from "remotion";

export const MyComposition = () => {
  return <Audio src={staticFile("audio.mp3")} />;
};

Remote URLs are also supported:

<Audio src="https://remotion.media/audio.mp3" />

By default, audio plays from the start, at full volume and full length. Multiple audio tracks can be layered by adding multiple <Audio> components.

Trimming

Use trimBefore and trimAfter to remove portions of the audio. Values are in frames.

const { fps } = useVideoConfig();

return (
  <Audio
    src={staticFile("audio.mp3")}
    trimBefore={2 * fps} // Skip the first 2 seconds
    trimAfter={10 * fps} // End at the 10 second mark
  />
);

The audio still starts playing at the beginning of the composition - only the specified portion is played.

Delaying

Wrap the audio in a <Sequence> to delay when it starts:

import { Sequence, staticFile } from "remotion";
import { Audio } from "@remotion/media";

const { fps } = useVideoConfig();

return (
  <Sequence from={1 * fps}>
    <Audio src={staticFile("audio.mp3")} />
  </Sequence>
);

The audio will start playing after 1 second.

Volume

Set a static volume (0 to 1):

<Audio src={staticFile("audio.mp3")} volume={0.5} />

Or use a callback for dynamic volume based on the current frame:

import { interpolate } from "remotion";

const { fps } = useVideoConfig();

return (
  <Audio
    src={staticFile("audio.mp3")}
    volume={(f) =>
      interpolate(f, [0, 1 * fps], [0, 1], { extrapolateRight: "clamp" })
    }
  />
);

The value of f starts at 0 when the audio begins to play, not the composition frame.

Muting

Use muted to silence the audio. It can be set dynamically:

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

return (
  <Audio
    src={staticFile("audio.mp3")}
    muted={frame >= 2 * fps && frame <= 4 * fps} // Mute between 2s and 4s
  />
);

Speed

Use playbackRate to change the playback speed:

<Audio src={staticFile("audio.mp3")} playbackRate={2} /> {/* 2x speed */}
<Audio src={staticFile("audio.mp3")} playbackRate={0.5} /> {/* Half speed */}

Reverse playback is not supported.

Looping

Use loop to loop the audio indefinitely:

<Audio src={staticFile("audio.mp3")} loop />

Use loopVolumeCurveBehavior to control how the frame count behaves when looping:

• "repeat": Frame count resets to 0 each loop (default)
• "extend": Frame count continues incrementing

<Audio
  src={staticFile("audio.mp3")}
  loop
  loopVolumeCurveBehavior="extend"
  volume={(f) => interpolate(f, [0, 300], [1, 0])} // Fade out over multiple loops
/>

Pitch

Use toneFrequency to adjust the pitch without affecting speed. Values range from 0.01 to 2:

<Audio
  src={staticFile("audio.mp3")}
  toneFrequency={1.5} // Higher pitch
/>
<Audio
  src={staticFile("audio.mp3")}
  toneFrequency={0.8} // Lower pitch
/>

Pitch shifting only works during server-side rendering, not in the Remotion Studio preview or in the <Player />.

Using calculateMetadata

Use calculateMetadata on a <Composition> to dynamically set duration, dimensions, and transform props before rendering.

<Composition
  id="MyComp"
  component={MyComponent}
  durationInFrames={300}
  fps={30}
  width={1920}
  height={1080}
  defaultProps={{ videoSrc: "https://remotion.media/video.mp4" }}
  calculateMetadata={calculateMetadata}
/>

Setting duration based on a video

Use the `getVideoDuration` and `getVideoDimensions` skills to get the video duration and dimensions:

import { CalculateMetadataFunction } from "remotion";
import { getVideoDuration } from "./get-video-duration";

const calculateMetadata: CalculateMetadataFunction<Props> = async ({
  props,
}) => {
  const durationInSeconds = await getVideoDuration(props.videoSrc);

  return {
    durationInFrames: Math.ceil(durationInSeconds * 30),
  };
};

Matching dimensions of a video

Use the `getVideoDimensions` skill to get the video dimensions:

import { CalculateMetadataFunction } from "remotion";
import { getVideoDuration } from "./get-video-duration";
import { getVideoDimensions } from "./get-video-dimensions";

const calculateMetadata: CalculateMetadataFunction<Props> = async ({
  props,
}) => {
  const dimensions = await getVideoDimensions(props.videoSrc);

  return {
    width: dimensions.width,
    height: dimensions.height,
  };
};

Setting duration based on multiple videos

const calculateMetadata: CalculateMetadataFunction<Props> = async ({
  props,
}) => {
  const metadataPromises = props.videos.map((video) =>
    getVideoDuration(video.src),
  );
  const allMetadata = await Promise.all(metadataPromises);

  const totalDuration = allMetadata.reduce(
    (sum, durationInSeconds) => sum + durationInSeconds,
    0,
  );

  return {
    durationInFrames: Math.ceil(totalDuration * 30),
  };
};

Setting a default outName

Set the default output filename based on props:

const calculateMetadata: CalculateMetadataFunction<Props> = async ({
  props,
}) => {
  return {
    defaultOutName: `video-${props.id}`, // .mp4 is added automatically
  };
};

Transforming props

Fetch data or transform props before rendering:

const calculateMetadata: CalculateMetadataFunction<Props> = async ({
  props,
  abortSignal,
}) => {
  const response = await fetch(props.dataUrl, { signal: abortSignal });
  const data = await response.json();

  return {
    props: {
      ...props,
      fetchedData: data,
    },
  };
};

The abortSignal cancels stale requests when props change in the Studio.

Return value

All fields are optional. Returned values override the <Composition> props:

• durationInFrames: Number of frames
• width: Composition width in pixels
• height: Composition height in pixels
• fps: Frames per second
• props: Transformed props passed to the component
• defaultOutName: Default output filename
• defaultCodec: Default codec for rendering

Checking if a video can be decoded

Use Mediabunny to check if a video can be decoded by the browser before attempting to play it.

First, install the right version of Mediabunny:

npx remotion add mediabunny

The canDecode() function

This function can be copy-pasted into any project.

import { Input, ALL_FORMATS, UrlSource } from "mediabunny";

export const canDecode = async (src: string) => {
  const input = new Input({
    formats: ALL_FORMATS,
    source: new UrlSource(src, {
      getRetryDelay: () => null,
    }),
  });

  try {
    await input.getFormat();
  } catch {
    return false;
  }

  const videoTrack = await input.getPrimaryVideoTrack();
  if (videoTrack && !(await videoTrack.canDecode())) {
    return false;
  }

  const audioTrack = await input.getPrimaryAudioTrack();
  if (audioTrack && !(await audioTrack.canDecode())) {
    return false;
  }

  return true;
};

Usage

const src = "https://remotion.media/video.mp4";
const isDecodable = await canDecode(src);

if (isDecodable) {
  console.log("Video can be decoded");
} else {
  console.log("Video cannot be decoded by this browser");
}

Using with Blob

For file uploads or drag-and-drop, use BlobSource:

import { Input, ALL_FORMATS, BlobSource } from "mediabunny";

export const canDecodeBlob = async (blob: Blob) => {
  const input = new Input({
    formats: ALL_FORMATS,
    source: new BlobSource(blob),
  });

  // Same validation logic as above
};

Charts in Remotion

Create charts using React code - HTML, SVG, and D3.js are all supported.

Disable all animations from third party libraries - they cause flickering. Drive all animations from useCurrentFrame().

Bar Chart

const STAGGER_DELAY = 5;
const frame = useCurrentFrame();
const { fps } = useVideoConfig();

const bars = data.map((item, i) => {
  const height = spring({
    frame,
    fps,
    delay: i * STAGGER_DELAY,
    config: { damping: 200 },
  });
  return <div style={{ height: height * item.value }} />;
});

Pie Chart

Animate segments using stroke-dashoffset, starting from 12 o'clock:

const progress = interpolate(frame, [0, 100], [0, 1]);
const circumference = 2 * Math.PI * radius;
const segmentLength = (value / total) * circumference;
const offset = interpolate(progress, [0, 1], [segmentLength, 0]);

<circle
  r={radius}
  cx={center}
  cy={center}
  fill="none"
  stroke={color}
  strokeWidth={strokeWidth}
  strokeDasharray={`${segmentLength} ${circumference}`}
  strokeDashoffset={offset}
  transform={`rotate(-90 ${center} ${center})`}
/>;

Line Chart / Path Animation

Use @remotion/paths for animating SVG paths (line charts, stock graphs, signatures).

Install: npx remotion add @remotion/paths Docs: https://remotion.dev/docs/paths.md

Convert data points to SVG path

type Point = { x: number; y: number };

const generateLinePath = (points: Point[]): string => {
  if (points.length < 2) return "";
  return points.map((p, i) => `${i === 0 ? "M" : "L"} ${p.x} ${p.y}`).join(" ");
};

Draw path with animation

import { evolvePath } from "@remotion/paths";

const path = "M 100 200 L 200 150 L 300 180 L 400 100";
const progress = interpolate(frame, [0, 2 * fps], [0, 1], {
  extrapolateLeft: "clamp",
  extrapolateRight: "clamp",
  easing: Easing.out(Easing.quad),
});

const { strokeDasharray, strokeDashoffset } = evolvePath(progress, path);

<path
  d={path}
  fill="none"
  stroke="#FF3232"
  strokeWidth={4}
  strokeDasharray={strokeDasharray}
  strokeDashoffset={strokeDashoffset}
/>;

Follow path with marker/arrow

import {
  getLength,
  getPointAtLength,
  getTangentAtLength,
} from "@remotion/paths";

const pathLength = getLength(path);
const point = getPointAtLength(path, progress * pathLength);
const tangent = getTangentAtLength(path, progress * pathLength);
const angle = Math.atan2(tangent.y, tangent.x);

<g
  style={{
    transform: `translate(${point.x}px, ${point.y}px) rotate(${angle}rad)`,
    transformOrigin: "0 0",
  }}
>
  <polygon points="0,0 -20,-10 -20,10" fill="#FF3232" />
</g>;

A <Composition> defines the component, width, height, fps and duration of a renderable video.

It normally is placed in the src/Root.tsx file.

import { Composition } from "remotion";
import { MyComposition } from "./MyComposition";

export const RemotionRoot = () => {
  return (
    <Composition
      id="MyComposition"
      component={MyComposition}
      durationInFrames={100}
      fps={30}
      width={1080}
      height={1080}
    />
  );
};

Default Props

Pass defaultProps to provide initial values for your component. Values must be JSON-serializable (Date, Map, Set, and staticFile() are supported).

import { Composition } from "remotion";
import { MyComposition, MyCompositionProps } from "./MyComposition";

export const RemotionRoot = () => {
  return (
    <Composition
      id="MyComposition"
      component={MyComposition}
      durationInFrames={100}
      fps={30}
      width={1080}
      height={1080}
      defaultProps={
        {
          title: "Hello World",
          color: "#ff0000",
        } satisfies MyCompositionProps
      }
    />
  );
};

Use type declarations for props rather than interface to ensure defaultProps type safety.

Folders

Use <Folder> to organize compositions in the sidebar. Folder names can only contain letters, numbers, and hyphens.

import { Composition, Folder } from "remotion";

export const RemotionRoot = () => {
  return (
    <>
      <Folder name="Marketing">
        <Composition id="Promo" /* ... */ />
        <Composition id="Ad" /* ... */ />
      </Folder>
      <Folder name="Social">
        <Folder name="Instagram">
          <Composition id="Story" /* ... */ />
          <Composition id="Reel" /* ... */ />
        </Folder>
      </Folder>
    </>
  );
};

Stills

Use <Still> for single-frame images. It does not require durationInFrames or fps.

import { Still } from "remotion";
import { Thumbnail } from "./Thumbnail";

export const RemotionRoot = () => {
  return (
    <Still id="Thumbnail" component={Thumbnail} width={1280} height={720} />
  );
};

Calculate Metadata

Use calculateMetadata to make dimensions, duration, or props dynamic based on data.

import { Composition, CalculateMetadataFunction } from "remotion";
import { MyComposition, MyCompositionProps } from "./MyComposition";

const calculateMetadata: CalculateMetadataFunction<
  MyCompositionProps
> = async ({ props, abortSignal }) => {
  const data = await fetch(`https://api.example.com/video/${props.videoId}`, {
    signal: abortSignal,
  }).then((res) => res.json());

  return {
    durationInFrames: Math.ceil(data.duration * 30),
    props: {
      ...props,
      videoUrl: data.url,
    },
  };
};

export const RemotionRoot = () => {
  return (
    <Composition
      id="MyComposition"
      component={MyComposition}
      durationInFrames={100} // Placeholder, will be overridden
      fps={30}
      width={1080}
      height={1080}
      defaultProps={{ videoId: "abc123" }}
      calculateMetadata={calculateMetadata}
    />
  );
};

The function can return props, durationInFrames, width, height, fps, and codec-related defaults. It runs once before rendering begins.

Nesting compositions within another

To add a composition within another composition, you can use the <Sequence> component with a width and height prop to specify the size of the composition.

<AbsoluteFill>
  <Sequence width={COMPOSITION_WIDTH} height={COMPOSITION_HEIGHT}>
    <CompositionComponent />
  </Sequence>
</AbsoluteFill>

Displaying captions in Remotion

This guide explains how to display captions in Remotion, assuming you already have captions in the `Caption` format.

Prerequisites

Read Transcribing audio for how to generate captions.

First, the `@remotion/captions` package needs to be installed. If it is not installed, use the following command:

npx remotion add @remotion/captions

Fetching captions

First, fetch your captions JSON file. Use `useDelayRender()` to hold the render until the captions are loaded:

import { useState, useEffect, useCallback } from "react";
import { AbsoluteFill, staticFile, useDelayRender } from "remotion";
import type { Caption } from "@remotion/captions";

export const MyComponent: React.FC = () => {
  const [captions, setCaptions] = useState<Caption[] | null>(null);
  const { delayRender, continueRender, cancelRender } = useDelayRender();
  const [handle] = useState(() => delayRender());

  const fetchCaptions = useCallback(async () => {
    try {
      // Assuming captions.json is in the public/ folder.
      const response = await fetch(staticFile("captions123.json"));
      const data = await response.json();
      setCaptions(data);
      continueRender(handle);
    } catch (e) {
      cancelRender(e);
    }
  }, [continueRender, cancelRender, handle]);

  useEffect(() => {
    fetchCaptions();
  }, [fetchCaptions]);

  if (!captions) {
    return null;
  }

  return <AbsoluteFill>{/* Render captions here */}</AbsoluteFill>;
};

Creating pages

Use createTikTokStyleCaptions() to group captions into pages. The combineTokensWithinMilliseconds option controls how many words appear at once:

import { useMemo } from "react";
import { createTikTokStyleCaptions } from "@remotion/captions";
import type { Caption } from "@remotion/captions";

// How often captions should switch (in milliseconds)
// Higher values = more words per page
// Lower values = fewer words (more word-by-word)
const SWITCH_CAPTIONS_EVERY_MS = 1200;

const { pages } = useMemo(() => {
  return createTikTokStyleCaptions({
    captions,
    combineTokensWithinMilliseconds: SWITCH_CAPTIONS_EVERY_MS,
  });
}, [captions]);

Rendering with Sequences

Map over the pages and render each one in a <Sequence>. Calculate the start frame and duration from the page timing:

import { Sequence, useVideoConfig, AbsoluteFill } from "remotion";
import type { TikTokPage } from "@remotion/captions";

const CaptionedContent: React.FC = () => {
  const { fps } = useVideoConfig();

  return (
    <AbsoluteFill>
      {pages.map((page, index) => {
        const nextPage = pages[index + 1] ?? null;
        const startFrame = (page.startMs / 1000) * fps;
        const endFrame = Math.min(
          nextPage ? (nextPage.startMs / 1000) * fps : Infinity,
          startFrame + (SWITCH_CAPTIONS_EVERY_MS / 1000) * fps,
        );
        const durationInFrames = endFrame - startFrame;

        if (durationInFrames <= 0) {
          return null;
        }

        return (
          <Sequence
            key={index}
            from={startFrame}
            durationInFrames={durationInFrames}
          >
            <CaptionPage page={page} />
          </Sequence>
        );
      })}
    </AbsoluteFill>
  );
};

White-space preservation

The captions are whitespace sensitive. You should include spaces in the text field before each word. Use whiteSpace: "pre" to preserve the whitespace in the captions.

Separate component for captions

Put captioning logic in a separate component. Make a new file for it.

Word highlighting

A caption page contains tokens which you can use to highlight the currently spoken word:

import { AbsoluteFill, useCurrentFrame, useVideoConfig } from "remotion";
import type { TikTokPage } from "@remotion/captions";

const HIGHLIGHT_COLOR = "#39E508";

const CaptionPage: React.FC<{ page: TikTokPage }> = ({ page }) => {
  const frame = useCurrentFrame();
  const { fps } = useVideoConfig();

  // Current time relative to the start of the sequence
  const currentTimeMs = (frame / fps) * 1000;
  // Convert to absolute time by adding the page start
  const absoluteTimeMs = page.startMs + currentTimeMs;

  return (
    <AbsoluteFill style={{ justifyContent: "center", alignItems: "center" }}>
      <div style={{ fontSize: 80, fontWeight: "bold", whiteSpace: "pre" }}>
        {page.tokens.map((token) => {
          const isActive =
            token.fromMs <= absoluteTimeMs && token.toMs > absoluteTimeMs;

          return (
            <span
              key={token.fromMs}
              style={{ color: isActive ? HIGHLIGHT_COLOR : "white" }}
            >
              {token.text}
            </span>
          );
        })}
      </div>
    </AbsoluteFill>
  );
};

Display captions alongside video content

By default, put the captions alongside the video content, so the captions are in sync. For each video, make a new captions JSON file.

<AbsoluteFill>
  <Video src={staticFile("video.mp4")} />
  <CaptionPage page={page} />
</AbsoluteFill>

Extracting frames from videos

Use Mediabunny to extract frames from videos at specific timestamps. This is useful for generating thumbnails, filmstrips, or processing individual frames.

The extractFrames() function

This function can be copy-pasted into any project.

import {
  ALL_FORMATS,
  Input,
  UrlSource,
  VideoSample,
  VideoSampleSink,
} from "mediabunny";

type Options = {
  track: { width: number; height: number };
  container: string;
  durationInSeconds: number | null;
};

export type ExtractFramesTimestampsInSecondsFn = (
  options: Options,
) => Promise<number[]> | number[];

export type ExtractFramesProps = {
  src: string;
  timestampsInSeconds: number[] | ExtractFramesTimestampsInSecondsFn;
  onVideoSample: (sample: VideoSample) => void;
  signal?: AbortSignal;
};

export async function extractFrames({
  src,
  timestampsInSeconds,
  onVideoSample,
  signal,
}: ExtractFramesProps): Promise<void> {
  using input = new Input({
    formats: ALL_FORMATS,
    source: new UrlSource(src),
  });

  const [durationInSeconds, format, videoTrack] = await Promise.all([
    input.computeDuration(),
    input.getFormat(),
    input.getPrimaryVideoTrack(),
  ]);

  if (!videoTrack) {
    throw new Error("No video track found in the input");
  }

  if (signal?.aborted) {
    throw new Error("Aborted");
  }

  const timestamps =
    typeof timestampsInSeconds === "function"
      ? await timestampsInSeconds({
          track: {
            width: videoTrack.displayWidth,
            height: videoTrack.displayHeight,
          },
          container: format.name,
          durationInSeconds,
        })
      : timestampsInSeconds;

  if (timestamps.length === 0) {
    return;
  }

  if (signal?.aborted) {
    throw new Error("Aborted");
  }

  const sink = new VideoSampleSink(videoTrack);

  for await (using videoSample of sink.samplesAtTimestamps(timestamps)) {
    if (signal?.aborted) {
      break;
    }

    if (!videoSample) {
      continue;
    }

    onVideoSample(videoSample);
  }
}

Basic usage

Extract frames at specific timestamps:

await extractFrames({
  src: "https://remotion.media/video.mp4",
  timestampsInSeconds: [0, 1, 2, 3, 4],
  onVideoSample: (sample) => {
    const canvas = document.createElement("canvas");
    canvas.width = sample.displayWidth;
    canvas.height = sample.displayHeight;
    const ctx = canvas.getContext("2d");
    sample.draw(ctx!, 0, 0);
  },
});

Creating a filmstrip

Use a callback function to dynamically calculate timestamps based on video metadata:

const canvasWidth = 500;
const canvasHeight = 80;
const fromSeconds = 0;
const toSeconds = 10;

await extractFrames({
  src: "https://remotion.media/video.mp4",
  timestampsInSeconds: async ({ track, durationInSeconds }) => {
    const aspectRatio = track.width / track.height;
    const amountOfFramesFit = Math.ceil(
      canvasWidth / (canvasHeight * aspectRatio),
    );
    const segmentDuration = toSeconds - fromSeconds;
    const timestamps: number[] = [];

    for (let i = 0; i < amountOfFramesFit; i++) {
      timestamps.push(
        fromSeconds + (segmentDuration / amountOfFramesFit) * (i + 0.5),
      );
    }

    return timestamps;
  },
  onVideoSample: (sample) => {
    console.log(`Frame at ${sample.timestamp}s`);

    const canvas = document.createElement("canvas");
    canvas.width = sample.displayWidth;
    canvas.height = sample.displayHeight;
    const ctx = canvas.getContext("2d");
    sample.draw(ctx!, 0, 0);
  },
});

Cancellation with AbortSignal

Cancel frame extraction after a timeout:

const controller = new AbortController();

setTimeout(() => controller.abort(), 5000);

try {
  await extractFrames({
    src: "https://remotion.media/video.mp4",
    timestampsInSeconds: [0, 1, 2, 3, 4],
    onVideoSample: (sample) => {
      using frame = sample;
      const canvas = document.createElement("canvas");
      canvas.width = frame.displayWidth;
      canvas.height = frame.displayHeight;
      const ctx = canvas.getContext("2d");
      frame.draw(ctx!, 0, 0);
    },
    signal: controller.signal,
  });

  console.log("Frame extraction complete!");
} catch (error) {
  console.error("Frame extraction was aborted or failed:", error);
}

Timeout with Promise.race

const controller = new AbortController();

const timeoutPromise = new Promise<never>((_, reject) => {
  const timeoutId = setTimeout(() => {
    controller.abort();
    reject(new Error("Frame extraction timed out after 10 seconds"));
  }, 10000);

  controller.signal.addEventListener("abort", () => clearTimeout(timeoutId), {
    once: true,
  });
});

try {
  await Promise.race([
    extractFrames({
      src: "https://remotion.media/video.mp4",
      timestampsInSeconds: [0, 1, 2, 3, 4],
      onVideoSample: (sample) => {
        using frame = sample;
        const canvas = document.createElement("canvas");
        canvas.width = frame.displayWidth;
        canvas.height = frame.displayHeight;
        const ctx = canvas.getContext("2d");
        frame.draw(ctx!, 0, 0);
      },
      signal: controller.signal,
    }),
    timeoutPromise,
  ]);

  console.log("Frame extraction complete!");
} catch (error) {
  console.error("Frame extraction was aborted or failed:", error);
}

FFmpeg in Remotion

ffmpeg and ffprobe do not need to be installed. They are available via the npx remotion ffmpeg and npx remotion ffprobe:

npx remotion ffmpeg -i input.mp4 output.mp3
npx remotion ffprobe input.mp4

Trimming videos

You have 2 options for trimming videos:

1. Preferred: Use the trimBefore and trimAfter props of the <Video> component. This is non-destructive, requires no re-encoding, and you can change the trim at any time.

import {Video} from '@remotion/media';

<Video src={staticFile('video.mp4')} trimBefore={5 * fps} trimAfter={10 * fps} />;

2. Use the FFmpeg command line. You MUST re-encode the video to avoid frozen frames at the start of the video. Only use this if you need a standalone trimmed file (e.g. for upload or external use).

# Re-encodes from the exact frame
npx remotion ffmpeg -ss 00:00:05 -i public/input.mp4 -to 00:00:10 -c:v libx264 -c:a aac public/output.mp4

Using fonts in Remotion

Google Fonts with @remotion/google-fonts

The recommended way to use Google Fonts. It's type-safe and automatically blocks rendering until the font is ready.

Prerequisites

First, the @remotion/google-fonts package needs to be installed. If it is not installed, use the following command:

npx remotion add @remotion/google-fonts # If project uses npm
bunx remotion add @remotion/google-fonts # If project uses bun
yarn remotion add @remotion/google-fonts # If project uses yarn
pnpm exec remotion add @remotion/google-fonts # If project uses pnpm

import { loadFont } from "@remotion/google-fonts/Lobster";

const { fontFamily } = loadFont();

export const MyComposition = () => {
  return <div style={{ fontFamily }}>Hello World</div>;
};

Preferrably, specify only needed weights and subsets to reduce file size:

import { loadFont } from "@remotion/google-fonts/Roboto";

const { fontFamily } = loadFont("normal", {
  weights: ["400", "700"],
  subsets: ["latin"],
});

Waiting for font to load

Use waitUntilDone() if you need to know when the font is ready:

import { loadFont } from "@remotion/google-fonts/Lobster";

const { fontFamily, waitUntilDone } = loadFont();

await waitUntilDone();

Local fonts with @remotion/fonts

For local font files, use the @remotion/fonts package.

Prerequisites

First, install @remotion/fonts:

npx remotion add @remotion/fonts # If project uses npm
bunx remotion add @remotion/fonts # If project uses bun
yarn remotion add @remotion/fonts # If project uses yarn
pnpm exec remotion add @remotion/fonts # If project uses pnpm

Loading a local font

Place your font file in the public/ folder and use loadFont():

import { loadFont } from "@remotion/fonts";
import { staticFile } from "remotion";

await loadFont({
  family: "MyFont",
  url: staticFile("MyFont-Regular.woff2"),
});

export const MyComposition = () => {
  return <div style={{ fontFamily: "MyFont" }}>Hello World</div>;
};

Loading multiple weights

Load each weight separately with the same family name:

import { loadFont } from "@remotion/fonts";
import { staticFile } from "remotion";

await Promise.all([
  loadFont({
    family: "Inter",
    url: staticFile("Inter-Regular.woff2"),
    weight: "400",
  }),
  loadFont({
    family: "Inter",
    url: staticFile("Inter-Bold.woff2"),
    weight: "700",
  }),
]);

Available options

loadFont({
  family: "MyFont", // Required: name to use in CSS
  url: staticFile("font.woff2"), // Required: font file URL
  format: "woff2", // Optional: auto-detected from extension
  weight: "400", // Optional: font weight
  style: "normal", // Optional: normal or italic
  display: "block", // Optional: font-display behavior
});

Using in components

Call loadFont() at the top level of your component or in a separate file that's imported early:

import { loadFont } from "@remotion/google-fonts/Montserrat";

const { fontFamily } = loadFont("normal", {
  weights: ["400", "700"],
  subsets: ["latin"],
});

export const Title: React.FC<{ text: string }> = ({ text }) => {
  return (
    <h1
      style={{
        fontFamily,
        fontSize: 80,
        fontWeight: "bold",
      }}
    >
      {text}
    </h1>
  );
};

Getting audio duration with Mediabunny

Mediabunny can extract the duration of an audio file. It works in browser, Node.js, and Bun environments.

Getting audio duration

```tsx title="get-audio-duration.ts" import { Input, ALL_FORMATS, UrlSource } from "mediabunny";

export const getAudioDuration = async (src: string) => { const input = new Input({ formats: ALL_FORMATS, source: new UrlSource(src, { getRetryDelay: () => null, }), });

const durationInSeconds = await input.computeDuration(); return durationInSeconds; };

## Usage

const duration = await getAudioDuration("https://remotion.media/audio.mp3"); console.log(duration); // e.g. 180.5 (seconds)

## Using with staticFile in Remotion

Make sure to wrap the file path in `staticFile()`:

import { staticFile } from "remotion";

const duration = await getAudioDuration(staticFile("audio.mp3"));

## In Node.js and Bun

Use `FileSource` instead of `UrlSource`:

import { Input, ALL_FORMATS, FileSource } from "mediabunny";

const input = new Input({ formats: ALL_FORMATS, source: new FileSource(file), // File object from input or drag-drop });

Getting video dimensions with Mediabunny

Mediabunny can extract the width and height of a video file. It works in browser, Node.js, and Bun environments.

Getting video dimensions

import { Input, ALL_FORMATS, UrlSource } from "mediabunny";

export const getVideoDimensions = async (src: string) => {
  const input = new Input({
    formats: ALL_FORMATS,
    source: new UrlSource(src, {
      getRetryDelay: () => null,
    }),
  });

  const videoTrack = await input.getPrimaryVideoTrack();
  if (!videoTrack) {
    throw new Error("No video track found");
  }

  return {
    width: videoTrack.displayWidth,
    height: videoTrack.displayHeight,
  };
};

Usage

const dimensions = await getVideoDimensions("https://remotion.media/video.mp4");
console.log(dimensions.width); // e.g. 1920
console.log(dimensions.height); // e.g. 1080

Using with local files

For local files, use FileSource instead of UrlSource:

import { Input, ALL_FORMATS, FileSource } from "mediabunny";

const input = new Input({
  formats: ALL_FORMATS,
  source: new FileSource(file), // File object from input or drag-drop
});

const videoTrack = await input.getPrimaryVideoTrack();
const width = videoTrack.displayWidth;
const height = videoTrack.displayHeight;

Using with staticFile in Remotion

import { staticFile } from "remotion";

const dimensions = await getVideoDimensions(staticFile("video.mp4"));

Getting video duration with Mediabunny

Mediabunny can extract the duration of a video file. It works in browser, Node.js, and Bun environments.

Getting video duration

import { Input, ALL_FORMATS, UrlSource } from "mediabunny";

export const getVideoDuration = async (src: string) => {
  const input = new Input({
    formats: ALL_FORMATS,
    source: new UrlSource(src, {
      getRetryDelay: () => null,
    }),
  });

  const durationInSeconds = await input.computeDuration();
  return durationInSeconds;
};

Usage

const duration = await getVideoDuration("https://remotion.media/video.mp4");
console.log(duration); // e.g. 10.5 (seconds)

Video files from the public/ directory

Make sure to wrap the file path in staticFile():

import { staticFile } from "remotion";

const duration = await getVideoDuration(staticFile("video.mp4"));

In Node.js and Bun

Use FileSource instead of UrlSource:

import { Input, ALL_FORMATS, FileSource } from "mediabunny";

const input = new Input({
  formats: ALL_FORMATS,
  source: new FileSource(file), // File object from input or drag-drop
});

const durationInSeconds = await input.computeDuration();

Using Animated images in Remotion

Basic usage

Use <AnimatedImage> to display a GIF, APNG, AVIF or WebP image synchronized with Remotion's timeline:

import { AnimatedImage, staticFile } from "remotion";

export const MyComposition = () => {
  return (
    <AnimatedImage src={staticFile("animation.gif")} width={500} height={500} />
  );
};

Remote URLs are also supported (must have CORS enabled):

<AnimatedImage
  src="https://example.com/animation.gif"
  width={500}
  height={500}
/>

Sizing and fit

Control how the image fills its container with the fit prop:

// Stretch to fill (default)
<AnimatedImage src={staticFile("animation.gif")} width={500} height={300} fit="fill" />

// Maintain aspect ratio, fit inside container
<AnimatedImage src={staticFile("animation.gif")} width={500} height={300} fit="contain" />

// Fill container, crop if needed
<AnimatedImage src={staticFile("animation.gif")} width={500} height={300} fit="cover" />

Playback speed

Use playbackRate to control the animation speed:

<AnimatedImage src={staticFile("animation.gif")} width={500} height={500} playbackRate={2} /> {/* 2x speed */}
<AnimatedImage src={staticFile("animation.gif")} width={500} height={500} playbackRate={0.5} /> {/* Half speed */}

Looping behavior

Control what happens when the animation finishes:

// Loop indefinitely (default)
<AnimatedImage src={staticFile("animation.gif")} width={500} height={500} loopBehavior="loop" />

// Play once, show final frame
<AnimatedImage src={staticFile("animation.gif")} width={500} height={500} loopBehavior="pause-after-finish" />

// Play once, then clear canvas
<AnimatedImage src={staticFile("animation.gif")} width={500} height={500} loopBehavior="clear-after-finish" />

Styling

Use the style prop for additional CSS (use width and height props for sizing):

<AnimatedImage
  src={staticFile("animation.gif")}
  width={500}
  height={500}
  style={{
    borderRadius: 20,
    position: "absolute",
    top: 100,
    left: 50,
  }}
/>

Getting GIF duration

Use getGifDurationInSeconds() from @remotion/gif to get the duration of a GIF.

npx remotion add @remotion/gif

import { getGifDurationInSeconds } from "@remotion/gif";
import { staticFile } from "remotion";

const duration = await getGifDurationInSeconds(staticFile("animation.gif"));
console.log(duration); // e.g. 2.5

This is useful for setting the composition duration to match the GIF:

import { getGifDurationInSeconds } from "@remotion/gif";
import { staticFile, CalculateMetadataFunction } from "remotion";

const calculateMetadata: CalculateMetadataFunction = async () => {
  const duration = await getGifDurationInSeconds(staticFile("animation.gif"));
  return {
    durationInFrames: Math.ceil(duration * 30),
  };
};

Alternative

If <AnimatedImage> does not work (only supported in Chrome and Firefox), you can use <Gif> from @remotion/gif instead.

npx remotion add @remotion/gif # If project uses npm
bunx remotion add @remotion/gif # If project uses bun
yarn remotion add @remotion/gif # If project uses yarn
pnpm exec remotion add @remotion/gif # If project uses pnpm

import { Gif } from "@remotion/gif";
import { staticFile } from "remotion";

export const MyComposition = () => {
  return <Gif src={staticFile("animation.gif")} width={500} height={500} />;
};

The <Gif> component has the same props as <AnimatedImage> but only supports GIF files.

Using images in Remotion

The <Img> component

Always use the <Img> component from remotion to display images:

import { Img, staticFile } from "remotion";

export const MyComposition = () => {
  return <Img src={staticFile("photo.png")} />;
};

Important restrictions

You MUST use the `<Img>` component from `remotion`. Do not use:

• Native HTML <img> elements
• Next.js <Image> component
• CSS background-image

The <Img> component ensures images are fully loaded before rendering, preventing flickering and blank frames during video export.

Local images with staticFile()

Place images in the public/ folder and use staticFile() to reference them:

my-video/
├─ public/
│  ├─ logo.png
│  ├─ avatar.jpg
│  └─ icon.svg
├─ src/
├─ package.json

import { Img, staticFile } from "remotion";

<Img src={staticFile("logo.png")} />;

Remote images

Remote URLs can be used directly without staticFile():

<Img src="https://example.com/image.png" />

Ensure remote images have CORS enabled.

For animated GIFs, use the <Gif> component from @remotion/gif instead.

Sizing and positioning

Use the style prop to control size and position:

<Img
  src={staticFile("photo.png")}
  style={{
    width: 500,
    height: 300,
    position: "absolute",
    top: 100,
    left: 50,
    objectFit: "cover",
  }}
/>

Dynamic image paths

Use template literals for dynamic file references:

import { Img, staticFile, useCurrentFrame } from "remotion";

const frame = useCurrentFrame();

// Image sequence
<Img src={staticFile(`frames/frame${frame}.png`)} />

// Selecting based on props
<Img src={staticFile(`avatars/${props.userId}.png`)} />

// Conditional images
<Img src={staticFile(`icons/${isActive ? "active" : "inactive"}.svg`)} />

This pattern is useful for:

• Image sequences (frame-by-frame animations)
• User-specific avatars or profile images
• Theme-based icons
• State-dependent graphics

Getting image dimensions

Use getImageDimensions() to get the dimensions of an image:

import { getImageDimensions, staticFile } from "remotion";

const { width, height } = await getImageDimensions(staticFile("photo.png"));

This is useful for calculating aspect ratios or sizing compositions:

import {
  getImageDimensions,
  staticFile,
  CalculateMetadataFunction,
} from "remotion";

const calculateMetadata: CalculateMetadataFunction = async () => {
  const { width, height } = await getImageDimensions(staticFile("photo.png"));
  return {
    width,
    height,
  };
};

Importing .srt subtitles into Remotion

If you have an existing .srt subtitle file, you can import it into Remotion using parseSrt() from @remotion/captions.

If you don't have a .srt file, read Transcribing audio for how to generate captions instead.

Prerequisites

First, the @remotion/captions package needs to be installed. If it is not installed, use the following command:

npx remotion add @remotion/captions # If project uses npm
bunx remotion add @remotion/captions # If project uses bun
yarn remotion add @remotion/captions # If project uses yarn
pnpm exec remotion add @remotion/captions # If project uses pnpm

Reading an .srt file

Use staticFile() to reference an .srt file in your public folder, then fetch and parse it:

import { useState, useEffect, useCallback } from "react";
import { AbsoluteFill, staticFile, useDelayRender } from "remotion";
import { parseSrt } from "@remotion/captions";
import type { Caption } from "@remotion/captions";

export const MyComponent: React.FC = () => {
  const [captions, setCaptions] = useState<Caption[] | null>(null);
  const { delayRender, continueRender, cancelRender } = useDelayRender();
  const [handle] = useState(() => delayRender());

  const fetchCaptions = useCallback(async () => {
    try {
      const response = await fetch(staticFile("subtitles.srt"));
      const text = await response.text();
      const { captions: parsed } = parseSrt({ input: text });
      setCaptions(parsed);
      continueRender(handle);
    } catch (e) {
      cancelRender(e);
    }
  }, [continueRender, cancelRender, handle]);

  useEffect(() => {
    fetchCaptions();
  }, [fetchCaptions]);

  if (!captions) {
    return null;
  }

  return <AbsoluteFill>{/* Use captions here */}</AbsoluteFill>;
};

Remote URLs are also supported - you can fetch() a remote file via URL instead of using staticFile().

Using imported captions

Once parsed, the captions are in the Caption format and can be used with all @remotion/captions utilities.

Light Leaks

This only works from Remotion 4.0.415 and up. Use npx remotion versions to check your Remotion version and npx remotion upgrade to upgrade your Remotion version.

<LightLeak> from @remotion/light-leaks renders a WebGL-based light leak effect. It reveals during the first half of its duration and retracts during the second half.

Typically used inside a <TransitionSeries.Overlay> to play over the cut point between two scenes. See the transitions rule for <TransitionSeries> and overlay usage.

Prerequisites

npx remotion add @remotion/light-leaks

Basic usage with TransitionSeries

import { TransitionSeries } from "@remotion/transitions";
import { LightLeak } from "@remotion/light-leaks";

<TransitionSeries>
  <TransitionSeries.Sequence durationInFrames={60}>
    <SceneA />
  </TransitionSeries.Sequence>
  <TransitionSeries.Overlay durationInFrames={30}>
    <LightLeak />
  </TransitionSeries.Overlay>
  <TransitionSeries.Sequence durationInFrames={60}>
    <SceneB />
  </TransitionSeries.Sequence>
</TransitionSeries>;

Props

• durationInFrames? — defaults to the parent sequence/composition duration. The effect reveals during the first half and retracts during the second half.
• seed? — determines the shape of the light leak pattern. Different seeds produce different patterns. Default: 0.
• hueShift? — rotates the hue in degrees (0–360). Default: 0 (yellow-to-orange). 120 = green, 240 = blue.

Customizing the look

import { LightLeak } from "@remotion/light-leaks";

// Blue-tinted light leak with a different pattern
<LightLeak seed={5} hueShift={240} />;

// Green-tinted light leak
<LightLeak seed={2} hueShift={120} />;

Standalone usage

<LightLeak> can also be used outside of <TransitionSeries>, for example as a decorative overlay in any composition:

import { AbsoluteFill } from "remotion";
import { LightLeak } from "@remotion/light-leaks";

const MyComp: React.FC = () => (
  <AbsoluteFill>
    <MyContent />
    <LightLeak durationInFrames={60} seed={3} />
  </AbsoluteFill>
);

Using Lottie Animations in Remotion

Prerequisites

First, the @remotion/lottie package needs to be installed. If it is not, use the following command:

npx remotion add @remotion/lottie # If project uses npm
bunx remotion add @remotion/lottie # If project uses bun
yarn remotion add @remotion/lottie # If project uses yarn
pnpm exec remotion add @remotion/lottie # If project uses pnpm

Displaying a Lottie file

To import a Lottie animation:

• Fetch the Lottie asset
• Wrap the loading process in delayRender() and continueRender()
• Save the animation data in a state
• Render the Lottie animation using the Lottie component from the @remotion/lottie package

import { Lottie, LottieAnimationData } from "@remotion/lottie";
import { useEffect, useState } from "react";
import { cancelRender, continueRender, delayRender } from "remotion";

export const MyAnimation = () => {
  const [handle] = useState(() => delayRender("Loading Lottie animation"));

  const [animationData, setAnimationData] =
    useState<LottieAnimationData | null>(null);

  useEffect(() => {
    fetch("https://assets4.lottiefiles.com/packages/lf20_zyquagfl.json")
      .then((data) => data.json())
      .then((json) => {
        setAnimationData(json);
        continueRender(handle);
      })
      .catch((err) => {
        cancelRender(err);
      });
  }, [handle]);

  if (!animationData) {
    return null;
  }

  return <Lottie animationData={animationData} />;
};

Styling and animating

Lottie supports the style prop to allow styles and animations:

return (
  <Lottie animationData={animationData} style={{ width: 400, height: 400 }} />
);

Maps can be added to a Remotion video with Mapbox. The Mapbox documentation has the API reference.

Prerequisites

Mapbox and @turf/turf need to be installed.

Search the project for lockfiles and run the correct command depending on the package manager:

If package-lock.json is found, use the following command:

npm i mapbox-gl @turf/turf @types/mapbox-gl

If bun.lock is found, use the following command:

bun i mapbox-gl @turf/turf @types/mapbox-gl

If yarn.lock is found, use the following command:

yarn add mapbox-gl @turf/turf @types/mapbox-gl

If pnpm-lock.yaml is found, use the following command:

pnpm i mapbox-gl @turf/turf @types/mapbox-gl

The user needs to create a free Mapbox account and create an access token by visiting https://console.mapbox.com/account/access-tokens/.

The mapbox token needs to be added to the .env file:

```txt title=".env" REMOTION_MAPBOX_TOKEN==pk.your-mapbox-access-token

## Adding a map

Here is a basic example of a map in Remotion.

import { useEffect, useMemo, useRef, useState } from "react"; import { AbsoluteFill, useDelayRender, useVideoConfig } from "remotion"; import mapboxgl, { Map } from "mapbox-gl";

export const lineCoordinates = [ [6.56158447265625, 46.059891147620725], [6.5691375732421875, 46.05679376154153], [6.5842437744140625, 46.05059898938315], [6.594886779785156, 46.04702502069337], [6.601066589355469, 46.0460718554722], [6.6089630126953125, 46.0365370783104], [6.6185760498046875, 46.018420689207964], ];

mapboxgl.accessToken = process.env.REMOTION_MAPBOX_TOKEN as string;

export const MyComposition = () => { const ref = useRef<HTMLDivElement>(null); const { delayRender, continueRender } = useDelayRender();

const { width, height } = useVideoConfig(); const [handle] = useState(() => delayRender("Loading map...")); const [map, setMap] = useState<Map | null>(null);

useEffect(() => { const _map = new Map({ container: ref.current!, zoom: 11.53, center: [6.5615, 46.0598], pitch: 65, bearing: 0, style: "⁠mapbox://styles/mapbox/standard", interactive: false, fadeDuration: 0, });

_map.on("style.load", () => { // Hide all features from the Mapbox Standard style const hideFeatures = [ "showRoadsAndTransit", "showRoads", "showTransit", "showPedestrianRoads", "showRoadLabels", "showTransitLabels", "showPlaceLabels", "showPointOfInterestLabels", "showPointsOfInterest", "showAdminBoundaries", "showLandmarkIcons", "showLandmarkIconLabels", "show3dObjects", "show3dBuildings", "show3dTrees", "show3dLandmarks", "show3dFacades", ]; for (const feature of hideFeatures) { _map.setConfigProperty("basemap", feature, false); }

_map.setConfigProperty("basemap", "colorTrunks", "rgba(0, 0, 0, 0)");

_map.addSource("trace", { type: "geojson", data: { type: "Feature", properties: {}, geometry: { type: "LineString", coordinates: lineCoordinates, }, }, }); _map.addLayer({ type: "line", source: "trace", id: "line", paint: { "line-color": "black", "line-width": 5, }, layout: { "line-cap": "round", "line-join": "round", }, }); });

_map.on("load", () => { continueRender(handle); setMap(_map); }); }, [handle, lineCoordinates]);

const style: React.CSSProperties = useMemo( () => ({ width, height, position: "absolute" }), [width, height], );

return <AbsoluteFill ref={ref} style={style} />; };

The following is important in Remotion:

- Animations must be driven by `useCurrentFrame()` and animations that Mapbox brings itself should be disabled. For example, the `fadeDuration` prop should be set to `0`, `interactive` should be set to `false`, etc.
- Loading the map should be delayed using `useDelayRender()` and the map should be set to `null` until it is loaded.
- The element containing the ref MUST have an explicit width and height and `position: "absolute"`.
- Do not add a `_map.remove();` cleanup function.

## Drawing lines

Unless I request it, do not add a glow effect to the lines.
Unless I request it, do not add additional points to the lines.

## Map style

By default, use the `mapbox://styles/mapbox/standard` style.  
Hide the labels from the base map style.

Unless I request otherwise, remove all features from the Mapbox Standard style.

// Hide all features from the Mapbox Standard style const hideFeatures = [ "showRoadsAndTransit", "showRoads", "showTransit", "showPedestrianRoads", "showRoadLabels", "showTransitLabels", "showPlaceLabels", "showPointOfInterestLabels", "showPointsOfInterest", "showAdminBoundaries", "showLandmarkIcons", "showLandmarkIconLabels", "show3dObjects", "show3dBuildings", "show3dTrees", "show3dLandmarks", "show3dFacades", ]; for (const feature of hideFeatures) { _map.setConfigProperty("basemap", feature, false); }

_map.setConfigProperty("basemap", "colorMotorways", "transparent"); _map.setConfigProperty("basemap", "colorRoads", "transparent"); _map.setConfigProperty("basemap", "colorTrunks", "transparent");

## Animating the camera

You can animate the camera along the line by adding a `useEffect` hook that updates the camera position based on the current frame.

Unless I ask for it, do not jump between camera angles.

import * as turf from "@turf/turf"; import { interpolate } from "remotion"; import { Easing } from "remotion"; import { useCurrentFrame, useVideoConfig, useDelayRender } from "remotion";

const animationDuration = 20; const cameraAltitude = 4000;

const frame = useCurrentFrame(); const { fps } = useVideoConfig(); const { delayRender, continueRender } = useDelayRender();

useEffect(() => { if (!map) { return; } const handle = delayRender("Moving point...");

const routeDistance = turf.length(turf.lineString(lineCoordinates));

const progress = interpolate( frame / fps, [0.00001, animationDuration], [0, 1], { easing: Easing.inOut(Easing.sin), extrapolateLeft: "clamp", extrapolateRight: "clamp", }, );

const camera = map.getFreeCameraOptions();

const alongRoute = turf.along( turf.lineString(lineCoordinates), routeDistance * progress, ).geometry.coordinates;

camera.lookAtPoint({ lng: alongRoute[0], lat: alongRoute[1], });

map.setFreeCameraOptions(camera); map.once("idle", () => continueRender(handle)); }, [lineCoordinates, fps, frame, handle, map]);

Notes:

IMPORTANT: Keep the camera by default so north is up.
IMPORTANT: For multi-step animations, set all properties at all stages (zoom, position, line progress) to prevent jumps. Override initial values.

- The progress is clamped to a minimum value to avoid the line being empty, which can lead to turf errors
- See [Timing](./timing.md) for more options for timing.
- Consider the dimensions of the composition and make the lines thick enough and the label font size large enough to be legible for when the composition is scaled down.

## Animating lines

### Straight lines (linear interpolation)

To animate a line that appears straight on the map, use linear interpolation between coordinates. Do NOT use turf's `lineSliceAlong` or `along` functions, as they use geodesic (great circle) calculations which appear curved on a Mercator projection.

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

useEffect(() => { if (!map) return;

const animationHandle = delayRender("Animating line...");

const progress = interpolate(frame, [0, durationInFrames - 1], [0, 1], { extrapolateLeft: "clamp", extrapolateRight: "clamp", easing: Easing.inOut(Easing.cubic), });

// Linear interpolation for a straight line on the map const start = lineCoordinates[0]; const end = lineCoordinates[1]; const currentLng = start[0] + (end[0] - start[0]) progress; const currentLat = start[1] + (end[1] - start[1]) progress;

const lineData: GeoJSON.Feature<GeoJSON.LineString> = { type: "Feature", properties: {}, geometry: { type: "LineString", coordinates: [start, [currentLng, currentLat]], }, };

const source = map.getSource("trace") as mapboxgl.GeoJSONSource; if (source) { source.setData(lineData); }

map.once("idle", () => continueRender(animationHandle)); }, [frame, map, durationInFrames]);

### Curved lines (geodesic/great circle)

To animate a line that follows the geodesic (great circle) path between two points, use turf's `lineSliceAlong`. This is useful for showing flight paths or the actual shortest distance on Earth.

import * as turf from "@turf/turf";

const routeLine = turf.lineString(lineCoordinates); const routeDistance = turf.length(routeLine);

const currentDistance = Math.max(0.001, routeDistance * progress); const slicedLine = turf.lineSliceAlong(routeLine, 0, currentDistance);

const source = map.getSource("route") as mapboxgl.GeoJSONSource; if (source) { source.setData(slicedLine); }

## Markers

Add labels, and markers where appropriate.

_map.addSource("markers", { type: "geojson", data: { type: "FeatureCollection", features: [ { type: "Feature", properties: { name: "Point 1" }, geometry: { type: "Point", coordinates: [-118.2437, 34.0522] }, }, ], }, });

_map.addLayer({ id: "city-markers", type: "circle", source: "markers", paint: { "circle-radius": 40, "circle-color": "#FF4444", "circle-stroke-width": 4, "circle-stroke-color": "#FFFFFF", }, });

_map.addLayer({ id: "labels", type: "symbol", source: "markers", layout: { "text-field": ["get", "name"], "text-font": ["DIN Pro Bold", "Arial Unicode MS Bold"], "text-size": 50, "text-offset": [0, 0.5], "text-anchor": "top", }, paint: { "text-color": "#FFFFFF", "text-halo-color": "#000000", "text-halo-width": 2, }, });

Make sure they are big enough. Check the composition dimensions and scale the labels accordingly.
For a composition size of 1920x1080, the label font size should be at least 40px.

IMPORTANT: Keep the `text-offset` small enough so it is close to the marker. Consider the marker circle radius. For a circle radius of 40, this is a good offset:

"text-offset": [0, 0.5],

## 3D buildings

To enable 3D buildings, use the following code:

_map.setConfigProperty("basemap", "show3dObjects", true); _map.setConfigProperty("basemap", "show3dLandmarks", true); _map.setConfigProperty("basemap", "show3dBuildings", true);

## Rendering

When rendering a map animation, make sure to render with the following flags:

npx remotion render --gl=angle --concurrency=1

Measuring DOM nodes in Remotion

Remotion applies a scale() transform to the video container, which affects values from getBoundingClientRect(). Use useCurrentScale() to get correct measurements.

Measuring element dimensions

import { useCurrentScale } from "remotion";
import { useRef, useEffect, useState } from "react";

export const MyComponent = () => {
  const ref = useRef<HTMLDivElement>(null);
  const scale = useCurrentScale();
  const [dimensions, setDimensions] = useState({ width: 0, height: 0 });

  useEffect(() => {
    if (!ref.current) return;
    const rect = ref.current.getBoundingClientRect();
    setDimensions({
      width: rect.width / scale,
      height: rect.height / scale,
    });
  }, [scale]);

  return <div ref={ref}>Content to measure</div>;
};

Measuring text in Remotion

Prerequisites

Install @remotion/layout-utils if it is not already installed:

npx remotion add @remotion/layout-utils

Measuring text dimensions

Use measureText() to calculate the width and height of text:

import { measureText } from "@remotion/layout-utils";

const { width, height } = measureText({
  text: "Hello World",
  fontFamily: "Arial",
  fontSize: 32,
  fontWeight: "bold",
});

Results are cached - duplicate calls return the cached result.

Fitting text to a width

Use fitText() to find the optimal font size for a container:

import { fitText } from "@remotion/layout-utils";

const { fontSize } = fitText({
  text: "Hello World",
  withinWidth: 600,
  fontFamily: "Inter",
  fontWeight: "bold",
});

return (
  <div
    style={{
      fontSize: Math.min(fontSize, 80), // Cap at 80px
      fontFamily: "Inter",
      fontWeight: "bold",
    }}
  >
    Hello World
  </div>
);

Checking text overflow

Use fillTextBox() to check if text exceeds a box:

import { fillTextBox } from "@remotion/layout-utils";

const box = fillTextBox({ maxBoxWidth: 400, maxLines: 3 });

const words = ["Hello", "World", "This", "is", "a", "test"];
for (const word of words) {
  const { exceedsBox } = box.add({
    text: word + " ",
    fontFamily: "Arial",
    fontSize: 24,
  });
  if (exceedsBox) {
    // Text would overflow, handle accordingly
    break;
  }
}

Best practices

Load fonts first: Only call measurement functions after fonts are loaded.

import { loadFont } from "@remotion/google-fonts/Inter";

const { fontFamily, waitUntilDone } = loadFont("normal", {
  weights: ["400"],
  subsets: ["latin"],
});

waitUntilDone().then(() => {
  // Now safe to measure
  const { width } = measureText({
    text: "Hello",
    fontFamily,
    fontSize: 32,
  });
});

Use validateFontIsLoaded: Catch font loading issues early:

measureText({
  text: "Hello",
  fontFamily: "MyCustomFont",
  fontSize: 32,
  validateFontIsLoaded: true, // Throws if font not loaded
});

Match font properties: Use the same properties for measurement and rendering:

const fontStyle = {
  fontFamily: "Inter",
  fontSize: 32,
  fontWeight: "bold" as const,
  letterSpacing: "0.5px",
};

const { width } = measureText({
  text: "Hello",
  ...fontStyle,
});

return <div style={fontStyle}>Hello</div>;

Avoid padding and border: Use outline instead of border to prevent layout differences:

<div style={{ outline: "2px solid red" }}>Text</div>

To make a video parametrizable, a Zod schema can be added to a composition.

First, zod must be installed .

Search the project for lockfiles and run the correct command depending on the package manager:

If package-lock.json is found, use the following command:

npm i zod

If bun.lockb is found, use the following command:

bun i zod

If yarn.lock is found, use the following command:

yarn add zod

If pnpm-lock.yaml is found, use the following command:

pnpm i zod

Then, a Zod schema can be defined alongside the component:

```tsx title="src/MyComposition.tsx" import { z } from "zod";

export const MyCompositionSchema = z.object({ title: z.string(), });

const MyComponent: React.FC<z.infer<typeof MyCompositionSchema>> = () => { return ( <div> <h1>{props.title}</h1> </div> ); };

In the root file, the schema can be passed to the composition:

import { Composition } from "remotion"; import { MycComponent, MyCompositionSchema } from "./MyComposition";

export const RemotionRoot = () => { return ( <Composition id="MyComposition" component={MyComponent} durationInFrames={100} fps={30} width={1080} height={1080} defaultProps={{ title: "Hello World" }} schema={MyCompositionSchema} /> ); };

Now, the user can edit the parameter visually in the sidebar.

All schemas that are supported by Zod are supported by Remotion.

Remotion requires that the top-level type is a z.object(), because the collection of props of a React component is always an object.

## Color picker

For adding a color picker, use `zColor()` from `@remotion/zod-types`.

If it is not installed, use the following command:

npx remotion add @remotion/zod-types # If project uses npm bunx remotion add @remotion/zod-types # If project uses bun yarn remotion add @remotion/zod-types # If project uses yarn pnpm exec remotion add @remotion/zod-types # If project uses pnpm

Then import `zColor` from `@remotion/zod-types`:

import { zColor } from "@remotion/zod-types";

Then use it in the schema:

export const MyCompositionSchema = z.object({ color: zColor(), });

Use <Sequence> to delay when an element appears in the timeline.

import { Sequence } from "remotion";

const {fps} = useVideoConfig();

<Sequence from={1 * fps} durationInFrames={2 * fps} premountFor={1 * fps}>
  <Title />
</Sequence>
<Sequence from={2 * fps} durationInFrames={2 * fps} premountFor={1 * fps}>
  <Subtitle />
</Sequence>

This will by default wrap the component in an absolute fill element. If the items should not be wrapped, use the layout prop:

<Sequence layout="none">
  <Title />
</Sequence>

Premounting

This loads the component in the timeline before it is actually played. Always premount any <Sequence>!

<Sequence premountFor={1 * fps}>
  <Title />
</Sequence>

Series

Use <Series> when elements should play one after another without overlap.

import { Series } from "remotion";

<Series>
  <Series.Sequence durationInFrames={45}>
    <Intro />
  </Series.Sequence>
  <Series.Sequence durationInFrames={60}>
    <MainContent />
  </Series.Sequence>
  <Series.Sequence durationInFrames={30}>
    <Outro />
  </Series.Sequence>
</Series>;

Same as with <Sequence>, the items will be wrapped in an absolute fill element by default when using <Series.Sequence>, unless the layout prop is set to none.

Series with overlaps

Use negative offset for overlapping sequences:

<Series>
  <Series.Sequence durationInFrames={60}>
    <SceneA />
  </Series.Sequence>
  <Series.Sequence offset={-15} durationInFrames={60}>
    {/* Starts 15 frames before SceneA ends */}
    <SceneB />
  </Series.Sequence>
</Series>

Frame References Inside Sequences

Inside a Sequence, useCurrentFrame() returns the local frame (starting from 0):

<Sequence from={60} durationInFrames={30}>
  <MyComponent />
  {/* Inside MyComponent, useCurrentFrame() returns 0-29, not 60-89 */}
</Sequence>

Nested Sequences

Sequences can be nested for complex timing:

<Sequence from={0} durationInFrames={120}>
  <Background />
  <Sequence from={15} durationInFrames={90} layout="none">
    <Title />
  </Sequence>
  <Sequence from={45} durationInFrames={60} layout="none">
    <Subtitle />
  </Sequence>
</Sequence>

Nesting compositions within another

To add a composition within another composition, you can use the <Sequence> component with a width and height prop to specify the size of the composition.

<AbsoluteFill>
  <Sequence width={COMPOSITION_WIDTH} height={COMPOSITION_HEIGHT}>
    <CompositionComponent />
  </Sequence>
</AbsoluteFill>

To include a sound effect, use the <Audio> tag:

import { Audio } from "@remotion/sfx";

<Audio src={"https://remotion.media/whoosh.wav"} />;

The following sound effects are available:

• https://remotion.media/whoosh.wav
• https://remotion.media/whip.wav
• https://remotion.media/page-turn.wav
• https://remotion.media/switch.wav
• https://remotion.media/mouse-click.wav
• https://remotion.media/shutter-modern.wav
• https://remotion.media/shutter-old.wav
• https://remotion.media/ding.wav
• https://remotion.media/bruh.wav
• https://remotion.media/vine-boom.wav
• https://remotion.media/windows-xp-error.wav

For more sound effects, search the internet. A good resource is https://github.com/kapishdima/soundcn/tree/main/assets.

Adaptive Silence Detection

Detect silent segments in video or audio files.

Requires FFmpeg — see ffmpeg.md for how to invoke it in Remotion projects.

Step 1: Measure loudness with loudnorm

Use the loudnorm filter in JSON mode to get the EBU R128 integrated loudness and gating threshold for each file:

npx remotion ffmpeg -i public/video.mov -map 0:a -af loudnorm=print_format=json -f null /dev/null

As output you will get:

• input_i: Integrated loudness (dB) — the overall perceived volume
• input_thresh: EBU R128 gating threshold (dB) — the level below which audio is considered too quiet to count toward loudness measurement

Step 2: Detect silences using adaptive threshold

Pass the input_thresh value from step 1 as the noise parameter to silencedetect:

npx remotion ffmpeg -i public/video.mov -map 0:a -af "silencedetect=noise=${THRESH}dB:d=0.5" -f null /dev/null

Parameters:

• noise: The threshold below which audio is considered silent. Use input_thresh from step 1.
• d: Minimum silence duration in seconds. 0.5 is a good default.

Interpreting the output

The filter outputs pairs of silence_start and silence_end timestamps:

[silencedetect] silence_start: 0
[silencedetect] silence_end: 2.241021 | silence_duration: 2.241021
[silencedetect] silence_start: 38.77425
[silencedetect] silence_end: 39.619604 | silence_duration: 0.845354

Identifying leading and trailing silence

• Leading silence: Consecutive silence segments starting at or near 0. If the first silence_start is > 0.5s, there is no leading silence.
• Trailing silence: The last silence segment that extends to (or near) the end of the file. Compare the last silence_end with the file's total duration.

When multiple silences are nearly contiguous at the start or end (gap < 0.2s), treat them as a single leading/trailing silence block.

Using with Remotion's <Video> component

Apply the detected trim points using trimBefore and trimAfter (values are in frames):

import { Video } from "@remotion/media";
import { staticFile, useVideoConfig } from "remotion";

const { fps } = useVideoConfig();

<Video
  src={staticFile("video.mov")}
  trimBefore={Math.floor(leadingEnd * fps)}
  trimAfter={Math.ceil(trailingStart * fps)}
/>

All captions must be processed in JSON. The captions must use the Caption type which is the following:

import type { Caption } from "@remotion/captions";

This is the definition:

type Caption = {
  text: string;
  startMs: number;
  endMs: number;
  timestampMs: number | null;
  confidence: number | null;
};

Generating captions

To transcribe video and audio files to generate captions, load the ./transcribe-captions.md file for more instructions.

Displaying captions

To display captions in your video, load the ./display-captions.md file for more instructions.

Importing captions

To import captions from a .srt file, load the ./import-srt-captions.md file for more instructions.

You can and should use TailwindCSS in Remotion, if TailwindCSS is installed in the project.

Don't use transition-* or animate-* classes - always animate using the useCurrentFrame() hook.

Tailwind must be installed and enabled first in a Remotion project - fetch https://www.remotion.dev/docs/tailwind using WebFetch for instructions.

Text animations

Based on useCurrentFrame(), reduce the string character by character to create a typewriter effect.

Typewriter Effect

See Typewriter for an advanced example with a blinking cursor and a pause after the first sentence.

Always use string slicing for typewriter effects. Never use per-character opacity.

Word Highlighting

See Word Highlight for an example for how a word highlight is animated, like with a highlighter pen.

Drive motion with interpolate() over explicit frame range. To customize timing, use `Easing.bezier`. The four parameters are the same as CSS cubic-bezier(x1, y1, x2, y2).

A simple linear interpolation is done using the interpolate function.

```ts title="Going from 0 to 1 over 100 frames" 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", });

## Bézier easing

Use `Easing.bezier(x1, y1, x2, y2)` inside the `interpolate` options object. The curve is identical in spirit to CSS animations and transitions, which helps when you are stealing timing from the web or from a designer’s spec.

import { interpolate, Easing } from "remotion";

const opacity = interpolate(frame, [0, 60], [0, 1], { easing: Easing.bezier(0.16, 1, 0.3, 1), extrapolateLeft: "clamp", extrapolateRight: "clamp", });

### Examples (copy-paste curves)

**1. Crisp UI entrance (strong ease-out, no overshoot)** — slows nicely into the rest value; similar to many system “deceleration” curves.

const enter = interpolate(frame, [0, 45], [0, 1], { easing: Easing.bezier(0.16, 1, 0.3, 1), extrapolateLeft: "clamp", extrapolateRight: "clamp", });

**2. Editorial / slow fade (balanced ease-in-out)** — symmetric acceleration and deceleration over a hold-friendly move.

const progress = interpolate(frame, [0, 90], [0, 1], { easing: Easing.bezier(0.45, 0, 0.55, 1), extrapolateLeft: "clamp", extrapolateRight: "clamp", });

**3. Playful overshoot (control point y > 1)** — a little past the target then settles; use sparingly for emphasis.

const pop = interpolate(frame, [0, 30], [0, 1], { easing: Easing.bezier(0.34, 1.56, 0.64, 1), extrapolateLeft: "clamp", extrapolateRight: "clamp", });

## Preset easings (`Easing.in` / `Easing.out` / named curves)

Easing can be added to the `interpolate` function without a custom cubic:

import { interpolate, Easing } from "remotion";

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

The default easing is `Easing.linear`.  
Convexities:

- `Easing.in` — starting slow and accelerating
- `Easing.out` — starting fast and slowing down
- `Easing.inOut`

Named curves (from most linear to most curved):

- `Easing.quad`
- `Easing.cubic` (good default when you do not need a custom cubic)
- `Easing.sin`
- `Easing.exp`
- `Easing.circle`

### Easing direction for enter/exit animations

Use `Easing.out` for enter animations (starts fast, decelerates into place) and `Easing.in` for exit animations (starts slow, accelerates away). This feels natural because elements arrive with momentum and leave with gravity. When you need a specific curve from design, prefer a single `Easing.bezier(...)` instead of stacking presets.

## Composing interpolations

When multiple properties share the same timing (e.g. a slide-in panel and a video shift), avoid duplicating the full interpolation for each property. Instead, create a single normalized progress value (0 to 1) and derive each property from it:

const slideIn = interpolate( frame, [slideInStart, slideInStart + slideInDuration], [0, 1], { easing: Easing.bezier(0.22, 1, 0.36, 1), extrapolateLeft: "clamp", extrapolateRight: "clamp", }, ); const slideOut = interpolate( frame, [slideOutStart, slideOutStart + slideOutDuration], [0, 1], { easing: Easing.in(Easing.cubic), extrapolateLeft: "clamp", extrapolateRight: "clamp" }, ); const progress = slideIn - slideOut;

// Derive multiple properties from the same progress const overlayX = interpolate(progress, [0, 1], [100, 0]); const videoX = interpolate(progress, [0, 1], [0, -20]); const opacity = interpolate(progress, [0, 1], [0, 1]);

The key idea: separate **timing** (when and how fast) from **mapping** (what values to animate between).

Transcribing audio

To transcribe audio to generate captions in Remotion, you can use the `transcribe()` function from the `@remotion/install-whisper-cpp` package.

Prerequisites

First, the @remotion/install-whisper-cpp package needs to be installed. If it is not installed, use the following command:

npx remotion add @remotion/install-whisper-cpp

Transcribing

Make a Node.js script to download Whisper.cpp and a model, and transcribe the audio.

import path from "path";
import {
  downloadWhisperModel,
  installWhisperCpp,
  transcribe,
  toCaptions,
} from "@remotion/install-whisper-cpp";
import fs from "fs";

const to = path.join(process.cwd(), "whisper.cpp");

await installWhisperCpp({
  to,
  version: "1.5.5",
});

await downloadWhisperModel({
  model: "medium.en",
  folder: to,
});

// Convert the audio to a 16KHz wav file first if needed:
// import {execSync} from 'child_process';
// execSync('ffmpeg -i /path/to/audio.mp4 -ar 16000 /path/to/audio.wav -y');

const whisperCppOutput = await transcribe({
  model: "medium.en",
  whisperPath: to,
  whisperCppVersion: "1.5.5",
  inputPath: "/path/to/audio123.wav",
  tokenLevelTimestamps: true,
});

// Optional: Apply our recommended postprocessing
const { captions } = toCaptions({
  whisperCppOutput,
});

// Write it to the public/ folder so it can be fetched from Remotion
fs.writeFileSync("captions123.json", JSON.stringify(captions, null, 2));

Transcribe each clip individually and create multiple JSON files.

See Displaying captions for how to display the captions in Remotion.

TransitionSeries

<TransitionSeries> arranges scenes and supports two ways to enhance the cut point between them:

• Transitions (<TransitionSeries.Transition>) — crossfade, slide, wipe, etc. between two scenes. Shortens the timeline because both scenes play simultaneously during the transition.
• Overlays (<TransitionSeries.Overlay>) — render an effect (e.g. a light leak) on top of the cut point without shortening the timeline.

Children are absolutely positioned.

Prerequisites

npx remotion add @remotion/transitions

Transition example

import { TransitionSeries, linearTiming } from "@remotion/transitions";
import { fade } from "@remotion/transitions/fade";

<TransitionSeries>
  <TransitionSeries.Sequence durationInFrames={60}>
    <SceneA />
  </TransitionSeries.Sequence>
  <TransitionSeries.Transition
    presentation={fade()}
    timing={linearTiming({ durationInFrames: 15 })}
  />
  <TransitionSeries.Sequence durationInFrames={60}>
    <SceneB />
  </TransitionSeries.Sequence>
</TransitionSeries>;

Overlay example

Any React component can be used as an overlay. For a ready-made effect, see the light-leaks rule.

import { TransitionSeries } from "@remotion/transitions";
import { LightLeak } from "@remotion/light-leaks";

<TransitionSeries>
  <TransitionSeries.Sequence durationInFrames={60}>
    <SceneA />
  </TransitionSeries.Sequence>
  <TransitionSeries.Overlay durationInFrames={20}>
    <LightLeak />
  </TransitionSeries.Overlay>
  <TransitionSeries.Sequence durationInFrames={60}>
    <SceneB />
  </TransitionSeries.Sequence>
</TransitionSeries>;

Mixing transitions and overlays

Transitions and overlays can coexist in the same <TransitionSeries>, but an overlay cannot be adjacent to a transition or another overlay.

import { TransitionSeries, linearTiming } from "@remotion/transitions";
import { fade } from "@remotion/transitions/fade";
import { LightLeak } from "@remotion/light-leaks";

<TransitionSeries>
  <TransitionSeries.Sequence durationInFrames={60}>
    <SceneA />
  </TransitionSeries.Sequence>
  <TransitionSeries.Overlay durationInFrames={30}>
    <LightLeak />
  </TransitionSeries.Overlay>
  <TransitionSeries.Sequence durationInFrames={60}>
    <SceneB />
  </TransitionSeries.Sequence>
  <TransitionSeries.Transition
    presentation={fade()}
    timing={linearTiming({ durationInFrames: 15 })}
  />
  <TransitionSeries.Sequence durationInFrames={60}>
    <SceneC />
  </TransitionSeries.Sequence>
</TransitionSeries>;

Transition props

<TransitionSeries.Transition> requires:

• presentation — the visual effect (e.g. fade(), slide(), wipe()).
• timing — controls speed and easing (e.g. linearTiming(), springTiming()).

Overlay props

<TransitionSeries.Overlay> accepts:

• durationInFrames — how long the overlay is visible (positive integer).
• offset? — shifts the overlay relative to the cut point center. Positive = later, negative = earlier. Default: 0.

Available transition types

Import transitions from their respective modules:

import { fade } from "@remotion/transitions/fade";
import { slide } from "@remotion/transitions/slide";
import { wipe } from "@remotion/transitions/wipe";
import { flip } from "@remotion/transitions/flip";
import { clockWipe } from "@remotion/transitions/clock-wipe";

Slide transition with direction

import { slide } from "@remotion/transitions/slide";

<TransitionSeries.Transition
  presentation={slide({ direction: "from-left" })}
  timing={linearTiming({ durationInFrames: 20 })}
/>;

Directions: "from-left", "from-right", "from-top", "from-bottom"

Timing options

import { linearTiming, springTiming } from "@remotion/transitions";

// Linear timing - constant speed
linearTiming({ durationInFrames: 20 });

// Spring timing - organic motion
springTiming({ config: { damping: 200 }, durationInFrames: 25 });

Duration calculation

Transitions overlap adjacent scenes, so the total composition length is shorter than the sum of all sequence durations. Overlays do not affect the total duration.

For example, with two 60-frame sequences and a 15-frame transition:

• Without transitions: 60 + 60 = 120 frames
• With transition: 60 + 60 - 15 = 105 frames

Adding an overlay between two other sequences does not change the total.

Getting the duration of a transition

Use the getDurationInFrames() method on the timing object:

import { linearTiming, springTiming } from "@remotion/transitions";

const linearDuration = linearTiming({
  durationInFrames: 20,
}).getDurationInFrames({ fps: 30 });
// Returns 20

const springDuration = springTiming({
  config: { damping: 200 },
}).getDurationInFrames({ fps: 30 });
// Returns calculated duration based on spring physics

For springTiming without an explicit durationInFrames, the duration depends on fps because it calculates when the spring animation settles.

Calculating total composition duration

import { linearTiming } from "@remotion/transitions";

const scene1Duration = 60;
const scene2Duration = 60;
const scene3Duration = 60;

const timing1 = linearTiming({ durationInFrames: 15 });
const timing2 = linearTiming({ durationInFrames: 20 });

const transition1Duration = timing1.getDurationInFrames({ fps: 30 });
const transition2Duration = timing2.getDurationInFrames({ fps: 30 });

const totalDuration =
  scene1Duration +
  scene2Duration +
  scene3Duration -
  transition1Duration -
  transition2Duration;
// 60 + 60 + 60 - 15 - 20 = 145 frames

Rendering Transparent Videos

Remotion can render transparent videos in two ways: as a ProRes video or as a WebM video.

Transparent ProRes

Ideal for when importing into video editing software.

CLI:

npx remotion render --image-format=png --pixel-format=yuva444p10le --codec=prores --prores-profile=4444 MyComp out.mov

Default in Studio (restart Studio after changing):

// remotion.config.ts
import { Config } from "@remotion/cli/config";

Config.setVideoImageFormat("png");
Config.setPixelFormat("yuva444p10le");
Config.setCodec("prores");
Config.setProResProfile("4444");

Setting it as the default export settings for a composition (using calculateMetadata):

import { CalculateMetadataFunction } from "remotion";

const calculateMetadata: CalculateMetadataFunction<Props> = async ({
  props,
}) => {
  return {
    defaultCodec: "prores",
    defaultVideoImageFormat: "png",
    defaultPixelFormat: "yuva444p10le",
    defaultProResProfile: "4444",
  };
};

<Composition
  id="my-video"
  component={MyVideo}
  durationInFrames={150}
  fps={30}
  width={1920}
  height={1080}
  calculateMetadata={calculateMetadata}
/>;

Transparent WebM (VP9)

Ideal for when playing in a browser.

CLI:

npx remotion render --image-format=png --pixel-format=yuva420p --codec=vp9 MyComp out.webm

Default in Studio (restart Studio after changing):

// remotion.config.ts
import { Config } from "@remotion/cli/config";

Config.setVideoImageFormat("png");
Config.setPixelFormat("yuva420p");
Config.setCodec("vp9");

Setting it as the default export settings for a composition (using calculateMetadata):

import { CalculateMetadataFunction } from "remotion";

const calculateMetadata: CalculateMetadataFunction<Props> = async ({
  props,
}) => {
  return {
    defaultCodec: "vp8",
    defaultVideoImageFormat: "png",
    defaultPixelFormat: "yuva420p",
  };
};

<Composition
  id="my-video"
  component={MyVideo}
  durationInFrames={150}
  fps={30}
  width={1920}
  height={1080}
  calculateMetadata={calculateMetadata}
/>;

Use <Sequence> with a negative from value to trim the start of an animation.

Trim the Beginning

A negative from value shifts time backwards, making the animation start partway through:

import { Sequence, useVideoConfig } from "remotion";

const fps = useVideoConfig();

<Sequence from={-0.5 * fps}>
  <MyAnimation />
</Sequence>;

The animation appears 15 frames into its progress - the first 15 frames are trimmed off. Inside <MyAnimation>, useCurrentFrame() starts at 15 instead of 0.

Trim the End

Use durationInFrames to unmount content after a specified duration:

<Sequence durationInFrames={1.5 * fps}>
  <MyAnimation />
</Sequence>

The animation plays for 45 frames, then the component unmounts.

Trim and Delay

Nest sequences to both trim the beginning and delay when it appears:

<Sequence from={30}>
  <Sequence from={-15}>
    <MyAnimation />
  </Sequence>
</Sequence>

The inner sequence trims 15 frames from the start, and the outer sequence delays the result by 30 frames.

Using videos in Remotion

Prerequisites

First, the @remotion/media package needs to be installed. If it is not, use the following command:

npx remotion add @remotion/media # If project uses npm
bunx remotion add @remotion/media # If project uses bun
yarn remotion add @remotion/media # If project uses yarn
pnpm exec remotion add @remotion/media # If project uses pnpm

Use <Video> from @remotion/media to embed videos into your composition.

import { Video } from "@remotion/media";
import { staticFile } from "remotion";

export const MyComposition = () => {
  return <Video src={staticFile("video.mp4")} />;
};

Remote URLs are also supported:

<Video src="https://remotion.media/video.mp4" />

Trimming

Use trimBefore and trimAfter to remove portions of the video. Values are in seconds.

const { fps } = useVideoConfig();

return (
  <Video
    src={staticFile("video.mp4")}
    trimBefore={2 * fps} // Skip the first 2 seconds
    trimAfter={10 * fps} // End at the 10 second mark
  />
);

Delaying

Wrap the video in a <Sequence> to delay when it appears:

import { Sequence, staticFile } from "remotion";
import { Video } from "@remotion/media";

const { fps } = useVideoConfig();

return (
  <Sequence from={1 * fps}>
    <Video src={staticFile("video.mp4")} />
  </Sequence>
);

The video will appear after 1 second.

Sizing and Position

Use the style prop to control size and position:

<Video
  src={staticFile("video.mp4")}
  style={{
    width: 500,
    height: 300,
    position: "absolute",
    top: 100,
    left: 50,
    objectFit: "cover",
  }}
/>

Volume

Set a static volume (0 to 1):

<Video src={staticFile("video.mp4")} volume={0.5} />

Or use a callback for dynamic volume based on the current frame:

import { interpolate } from "remotion";

const { fps } = useVideoConfig();

return (
  <Video
    src={staticFile("video.mp4")}
    volume={(f) =>
      interpolate(f, [0, 1 * fps], [0, 1], { extrapolateRight: "clamp" })
    }
  />
);

Use muted to silence the video entirely:

<Video src={staticFile("video.mp4")} muted />

Speed

Use playbackRate to change the playback speed:

<Video src={staticFile("video.mp4")} playbackRate={2} /> {/* 2x speed */}
<Video src={staticFile("video.mp4")} playbackRate={0.5} /> {/* Half speed */}

Reverse playback is not supported.

Looping

Use loop to loop the video indefinitely:

<Video src={staticFile("video.mp4")} loop />

Use loopVolumeCurveBehavior to control how the frame count behaves when looping:

• "repeat": Frame count resets to 0 each loop (for volume callback)
• "extend": Frame count continues incrementing

<Video
  src={staticFile("video.mp4")}
  loop
  loopVolumeCurveBehavior="extend"
  volume={(f) => interpolate(f, [0, 300], [1, 0])} // Fade out over multiple loops
/>

Pitch

Use toneFrequency to adjust the pitch without affecting speed. Values range from 0.01 to 2:

<Video
  src={staticFile("video.mp4")}
  toneFrequency={1.5} // Higher pitch
/>
<Video
  src={staticFile("video.mp4")}
  toneFrequency={0.8} // Lower pitch
/>

Pitch shifting only works during server-side rendering, not in the Remotion Studio preview or in the <Player />.

Adding AI voiceover to a Remotion composition

Use ElevenLabs TTS to generate speech audio per scene, then use `calculateMetadata` to dynamically size the composition to match the audio.

Prerequisites

By default this guide uses ElevenLabs as the TTS provider (ELEVENLABS_API_KEY environment variable). Users may substitute any TTS service that can produce an audio file.

If the user has not specified a TTS provider, recommend ElevenLabs and ask for their API key.

Ensure the environment variable is available when running the generation script:

node --strip-types generate-voiceover.ts

Generating audio with ElevenLabs

Create a script that reads the config, calls the ElevenLabs API for each scene, and writes MP3 files to the public/ directory so Remotion can access them via staticFile().

The core API call for a single scene:

``ts title="generate-voiceover.ts" const response = await fetch( https://api.elevenlabs.io/v1/text-to-speech/${voiceId}`, { method: "POST", headers: { "xi-api-key": process.env.ELEVENLABS_API_KEY!, "Content-Type": "application/json", Accept: "audio/mpeg", }, body: JSON.stringify({ text: "Welcome to the show.", model_id: "eleven_multilingual_v2", voice_settings: { stability: 0.5, similarity_boost: 0.75, style: 0.3, }, }), }, );

const audioBuffer = Buffer.from(await response.arrayBuffer()); writeFileSync(public/voiceover/${compositionId}/${scene.id}.mp3, audioBuffer);

## Dynamic composition duration with calculateMetadata

Use [`calculateMetadata`](./calculate-metadata.md) to measure the [audio durations](./get-audio-duration.md) and set the composition length accordingly.

import { CalculateMetadataFunction, staticFile } from "remotion"; import { getAudioDuration } from "./get-audio-duration";

const FPS = 30;

const SCENE_AUDIO_FILES = [ "voiceover/my-comp/scene-01-intro.mp3", "voiceover/my-comp/scene-02-main.mp3", "voiceover/my-comp/scene-03-outro.mp3", ];

export const calculateMetadata: CalculateMetadataFunction<Props> = async ({ props, }) => { const durations = await Promise.all( SCENE_AUDIO_FILES.map((file) => getAudioDuration(staticFile(file))), );

const sceneDurations = durations.map((durationInSeconds) => { return durationInSeconds * FPS; });

return { durationInFrames: Math.ceil(sceneDurations.reduce((sum, d) => sum + d, 0)), }; };

The computed `sceneDurations` are passed into the component via a `voiceover` prop so the component knows how long each scene should be.

If the composition uses [`<TransitionSeries>`](./transitions.md), subtract the overlap from total duration: [./transitions.md#calculating-total-composition-duration](./transitions.md#calculating-total-composition-duration)

## Rendering audio in the component

See [audio.md](./audio.md) for more information on how to render audio in the component.

## Delaying audio start

See [audio.md#delaying](./audio.md#delaying) for more information on how to delay the audio start.