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

name, description, metadata

name	description	metadata
can-decode	Check if a video can be decoded by the browser using Mediabunny	tags decode, validation, video, audio, compatibility, browser

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.

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
};