remotion-dev/remotion · error · Error

Unknown fit: ${fit}

Error message

Unknown fit: ${fit}

What it means

calculateImageFit computes source/destination rectangles for drawing an image into a canvas for the 'contain', 'cover', and 'fill' strategies. The switch is intended to be exhaustive over the ImageFit union; the default branch throws to surface any value that escapes the union (typically via TypeScript escape hatches).

Source

Thrown at packages/core/src/calculate-image-fit.ts:70

				canvasSize.height / imageSize.height,
			);
			const centerX = (canvasSize.width - imageSize.width * ratio) / 2;
			const centerY = (canvasSize.height - imageSize.height * ratio) / 2;

			return [
				0,
				0,
				imageSize.width,
				imageSize.height,
				centerX,
				centerY,
				imageSize.width * ratio,
				imageSize.height * ratio,
			];
		}

		default:
			throw new Error('Unknown fit: ' + fit);
	}
};

View on GitHub (pinned to 78fe4bb3fd)

Solutions

1. Use one of the supported values: 'contain', 'cover', or 'fill'.
2. If accepting user/config input, validate against an allowlist before calling.
3. Map unsupported fit values to the closest supported one at the boundary.

Example fix

// before
calculateImageFit('scale-to-fill' as ImageFit, img, canvas)

// after
calculateImageFit('fill', img, canvas)

const ALLOWED_FITS = new Set(['contain', 'cover', 'fill']);
if (!ALLOWED_FITS.has(fit)) {
  fit = 'contain'; // or throw your own error
}

const isImageFit = (v: unknown): v is 'contain' | 'cover' | 'fill' =>
  v === 'contain' || v === 'cover' || v === 'fill';

When it happens

Trigger: Calling calculateImageFit('crop', ...) or calculateImageFit('scale-to-fill', ...). Usually reached by casting a string to ImageFit via 'as any'/'as ImageFit' or by passing user input that wasn't validated against the allowed set.

Common situations: Integrating a design tool's fit vocabulary (which has more options than Remotion supports); passing a runtime string from a config file; copy-pasting a fit value from another library.

Related errors

• inputRange must contain only numbers
• outputStyles must contain only objects
• Argument passed to "${api}" for param "${param}" is undefine
• setImageSequence accepts a Boolean Value
• outputLocation must be a string but got ${typeof newOutputLo

AI-assisted analysis of remotion-dev/remotion@78fe4bb3fd (2026-08-12). Data as JSON: /api/errors/ba37ab8e4371a628. Report an issue: GitHub.