A `` defines the component, width, height, fps and duration of a renderable video.
It normally is placed in the `src/Root.tsx` file.
```tsx
import { Composition } from "remotion";
import { MyComposition } from "./MyComposition";
export const RemotionRoot = () => {
return (
);
};
```
## Default Props
Pass `defaultProps` to provide initial values for your component.
Values must be JSON-serializable (`Date`, `Map`, `Set`, and `staticFile()` are supported).
```tsx
import { Composition } from "remotion";
import { MyComposition, MyCompositionProps } from "./MyComposition";
export const RemotionRoot = () => {
return (
);
};
```
Use `type` declarations for props rather than `interface` to ensure `defaultProps` type safety.
## Folders
Use `` to organize compositions in the sidebar.
Folder names can only contain letters, numbers, and hyphens.
```tsx
import { Composition, Folder } from "remotion";
export const RemotionRoot = () => {
return (
` for single-frame images. It does not require `durationInFrames` or `fps`.
```tsx
import { Still } from "remotion";
import { Thumbnail } from "./Thumbnail";
export const RemotionRoot = () => {
return (
);
};
```
## Calculate Metadata
Use `calculateMetadata` to make dimensions, duration, or props dynamic based on data.
```tsx
import { Composition, CalculateMetadataFunction } from "remotion";
import { MyComposition, MyCompositionProps } from "./MyComposition";
const calculateMetadata: CalculateMetadataFunction = 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 (
);
};
```
The function can return `props`, `durationInFrames`, `width`, `height`, `fps`, and codec-related defaults. It runs once before rendering begins.
Source: claude-code-templates (MIT). See About Us for full credits.