remotion-dev/remotion · error

No dimensions found for bRoll:

Error message

No dimensions found for bRoll: 

What it means

getBRollDimensions fetches video metadata for a b-roll source with getVideoMetadata and needs dimensions to size the b-roll asset. When the returned metadata lacks a dimensions field, the function cannot proceed and throws, naming the offending source URL. This typically means the video could not be probed (unsupported/corrupt file) or the metadata did not include video tracks.

Solutions

1. Verify bRoll.source is a valid, decodable video file with video dimensions (test in a browser `<video>` tag)
2. Fix the URL: ensure the file exists, is served with correct MIME type, and is CORS-accessible
3. Re-encode the asset to H.264/MP4 with a video track if the codec is unsupported
4. Handle the error by falling back to explicit assetWidth/assetHeight supplied by the caller

Example fix

// before
const bRoll = {source: 'audio.mp3'}; // no video track
// after
const bRoll = {source: 'clip.mp4'}; // video with dimensions
// or validate first:
const meta = await getVideoMetadata({src: bRoll.source, includeDuration: false});
if (!meta.dimensions) throw new Error(`Unusable video: ${bRoll.source}`);

const meta = await getVideoMetadata({src: bRoll.source, includeDuration: false});
if (!meta.dimensions) {
  throw new Error(`Source has no video dimensions: ${bRoll.source}`);
}

const hasDimensions = (m: Awaited<ReturnType<typeof getVideoMetadata>>): m is typeof m & {dimensions: {width: number; height: number}} =>
  m.dimensions != null;

try {
  const dims = await getBRollDimensions(bRoll);
} catch (e) {
  if (e.message.startsWith('No dimensions found for bRoll')) {
    // fall back to default dimensions or skip the asset
  }
}

When it happens

Trigger: Calling getBRollDimensions with a bRoll.source pointing at a video whose getVideoMetadata result has no dimensions — e.g. an audio-only file, a corrupt or unsupported codec, or a src that failed to fully load.

Common situations: Pointing bRoll.source at an audio file or image instead of a video; a broken/404 or CORS-blocked URL; a video codec the browser cannot decode so no video track metadata is available.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• A custom role ARN must either be "undefined" or a string…
• A "duration" of a spring is NaN, which it must not be
• A "duration" of a spring must be a "number" but is
• A "duration" of a spring must be finite, but is
• A "duration" of a spring must be positive, but is

AI-assisted analysis of remotion-dev/remotion@46a3a6bf13 (2026-09-18). Data as JSON: /api/errors/0d4b7616c0151a4b. Report an issue: GitHub.

Appendix: source

Thrown at packages/template-recorder/remotion/layout/get-broll-dimensions.ts:41

  ) {
    const { width, height } = await getImageDimensions(bRoll.source);
    return {
      ...bRoll,
      type: "image",
      assetWidth: width,
      assetHeight: height,
    };
  }

  if (
    videoFileExtensions.some((ext) => bRoll.source.toLowerCase().endsWith(ext))
  ) {
    const metadata = await getVideoMetadata({
      src: bRoll.source,
      includeDuration: false,
    });
    if (!metadata.dimensions) {
      throw new Error("No dimensions found for bRoll: " + bRoll.source);
    }

    return {
      ...bRoll,
      type: "video",
      assetWidth: metadata.dimensions.width,
      assetHeight: metadata.dimensions.height,
    };
  }

  throw new Error(
    `Unsupported file extension for bRoll: ${bRoll.source}. Only ${[...imageFileExtensions, ...videoFileExtensions].join(", ")} are supported.`,
  );
};

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