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Emitting Artifactsv4.0.176

Sometimes you wish to generate additional files when rendering your video. For example:

  • A .srt subtitle file
  • A .txt containing chapters of the video
  • A CREDITS file for the assets used in the video
  • Debug information from the render.

You can use the <Artifact> component to emit arbitrary files from your video.

note

Emitting artifacts is not currently supported by @remotion/cloudrun.

Example​

MyComp.tsx
tsx
import React from 'react';
import {Artifact, useCurrentFrame} from 'remotion';
import {generateSubtitles} from './subtitles';
 
export const MyComp: React.FC = () => {
  const frame = useCurrentFrame();
  return (
    <>
      {frame === 0 ? (
        <Artifact filename="captions.srt" content={generateSubtitles()} />
      ) : null}
    </>
  );
};
MyComp.tsx
tsx
import React from 'react';
import {Artifact, useCurrentFrame} from 'remotion';
import {generateSubtitles} from './subtitles';
 
export const MyComp: React.FC = () => {
  const frame = useCurrentFrame();
  return (
    <>
      {frame === 0 ? (
        <Artifact filename="captions.srt" content={generateSubtitles()} />
      ) : null}
    </>
  );
};

Rules of artifacts​

The asset should only be rendered for one single frame of the video. Otherwise, the asset will get emitted multiple times.

It is possible to emit multiple assets, but they may not have the same filename.


For the content prop it is possible to pass a string, or a Uint8Array for binary data. Passing an Uint8Array should not be considered faster due to it having to be serialized.


Receiving artifacts​

In the CLI or Studio​

Artifacts get saved to out/[composition-id]/[filename] when rendering a video.

Using renderMedia(), renderStill() or renderFrames()​

Use the onArtifact callback to receive the artifacts.

render.mjs
tsx
import type {VideoConfig} from 'remotion';
 
const composition: VideoConfig = {
  width: 100,
  height: 100,
  fps: 30,
  defaultProps: {},
  props: {},
  defaultCodec: null,
  id: 'hi',
  durationInFrames: 100,
};
const serveUrl = 'http://localhost:8080';
const inputProps = {};
 
render.mjs
tsx
import type {VideoConfig} from 'remotion';
 
const composition: VideoConfig = {
  width: 100,
  height: 100,
  fps: 30,
  defaultProps: {},
  props: {},
  defaultCodec: null,
  id: 'hi',
  durationInFrames: 100,
};
const serveUrl = 'http://localhost:8080';
const inputProps = {};