remotion-dev/remotion · error · Error

The "${name}" prop ${location} must be one of ${validCodecs.

Error message

The "${name}" prop ${location} must be one of ${validCodecs.join(', ')}, but you passed ${defaultCodec}.

What it means

`validateCodec` rejects a codec string that is not in `validCodecs` (`h264, h265, vp8, vp9, av1, mp3, aac, wav, prores, h264-mkv, h264-ts, gif`). The match is case-sensitive. This guards both the `defaultCodec` from `calculateMetadata` and the `codec` argument to serverless render APIs.

Source

Thrown at packages/core/src/validation/validate-default-codec.ts:20

import {validCodecs} from '../codec';

export function validateCodec(
	defaultCodec: unknown,
	location: string,
	name: string,
): asserts defaultCodec is CodecOrUndefined {
	if (typeof defaultCodec === 'undefined') {
		return;
	}

	if (typeof defaultCodec !== 'string') {
		throw new TypeError(
			`The "${name}" prop ${location} must be a string, but you passed a value of type ${typeof defaultCodec}.`,
		);
	}

	if (!validCodecs.includes(defaultCodec as Codec)) {
		throw new Error(
			`The "${name}" prop ${location} must be one of ${validCodecs.join(
				', ',
			)}, but you passed ${defaultCodec}.`,
		);
	}
}

View on GitHub (pinned to 78fe4bb3fd)

Solutions

1. Use one of the exact lowercase values listed in the error.
2. For MP4 video use `'h264'` (or `'h265'`); for audio-only use `'mp3'`/`'aac'`/`'wav'`.
3. Import the `Codec` type so the editor autocompletes valid values.
4. Check `validCodecs` from `@remotion/renderer`/core if unsure.

Example fix

// before
renderMediaOnLambda({codec: 'H.264', ...})
// after
renderMediaOnLambda({codec: 'h264', ...})

import {validCodecs} from '@remotion/core/codec';
if (!validCodecs.includes(codec)) {
  throw new Error('Unsupported codec: ' + codec + '. Use one of ' + validCodecs.join(', '));
}

const isValidCodec = (c) => validCodecs.includes(c);

When it happens

Trigger: Passing a codec string that is misspelled, differently cased (`'H264'`, `'H.264'`, `'x264'`), uses a dot/dash variant (`'h.264'`, `'h-264'`), or names a codec Remotion does not support (`'webm'`, `'mkv'`, `'mp4'`).

Common situations: Typos; assuming case-insensitivity; using a container name instead of a codec; copying a codec name from another tool's vocabulary; version change where a codec was renamed or removed.

Related errors

• The "${name}" prop ${location} must be a string, but you pas
• "${name}" must be one of ${variants.join(', ')}
• "codec" must be a string
• '${codec}' is not a valid codec for GCP Cloud Run. The follo
• Value for ${JSON.stringify(key)} must be one of ${Object.key

AI-assisted analysis of remotion-dev/remotion@78fe4bb3fd (2026-08-12). Data as JSON: /api/errors/88e11c059923dbd9. Report an issue: GitHub.