remotion-dev/remotion · error · TypeError

Invalid LUT content on line

Error message

Invalid LUT content on line ${lineNumber}: LUT_3D_SIZE must be declared before the color data

What it means

This TypeError enforces ordering in .cube LUT files: the parser must know the LUT_3D_SIZE grid dimension before it can interpret or count color rows, since the row count and triplet layout depend on it. Within parseCubeLut, `size` starts as null and is only set when the LUT_3D_SIZE header line is parsed; if a color-data row (a line whose first token is numeric, not an uppercase directive) arrives while size is still null, the file lacks the required header before its data section. It signals a malformed .cube file, so the fix is to add the LUT_3D_SIZE declaration above the color rows.

Solutions

Add a LUT_3D_SIZE declaration before the first color row with the correct grid dimension
Verify the row count equals size^3 after adding the header
Re-export the LUT so the header is included

Example fix

// before
0 0 0
0 0 1
// after
LUT_3D_SIZE 2
0 0 0
0 0 1

Defensive patterns

Strategy: validation

Validate before calling

const firstNonEmpty = content.split(/\r?\n/).map((l) => l.split('#')[0].trim()).find((l) => l.length > 0);
if (firstNonEmpty && /^\d/.test(firstNonEmpty)) throw new Error('File starts with color data: LUT_3D_SIZE missing');

Type guard

null

Try / catch

try {
  const lut = parseCubeLut(content);
} catch (e) {
  if (e instanceof TypeError && e.message.includes('must be declared before the color data')) {
    // insert the LUT_3D_SIZE header or reject the malformed file
  } else throw e;
}

Prevention

Never strip headers when preprocessing LUT files
Validate that the first non-empty, non-comment line is a header directive

When it happens

Trigger: A .cube file starts directly with color rows like '0 0 0' without a preceding 'LUT_3D_SIZE N' line passed to parseCubeLut().

Common situations: Header stripped by an editor or script, files truncated at the top, or data generated without emitting the size header.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

AI-assisted analysis of remotion-dev/remotion@46a3a6bf13 (2026-09-18). Data as JSON: /api/errors/0fb8b2e55d875261. Report an issue: GitHub.

Appendix: source

Thrown at packages/effects/src/lut/parse-cube-lut.ts:165

			}

			domainMax = parseTriplet({
				values,
				lineNumber,
				label: 'DOMAIN_MAX',
			});
			hasDomainMax = true;
			continue;
		}

		if (/^[A-Z_]/i.test(keyword)) {
			throw new TypeError(
				`Invalid LUT content on line ${lineNumber}: unsupported directive "${keyword}"`,
			);
		}

		if (size === null) {
			throw new TypeError(
				`Invalid LUT content on line ${lineNumber}: LUT_3D_SIZE must be declared before the color data`,
			);
		}

		parseTriplet({
			values: [keyword, ...values],
			lineNumber,
			label: 'color row',
		});
		dataStarted = true;
		dataRows++;

		const maxDataRows = size ** 3;
		if (dataRows > maxDataRows) {
			throw new TypeError(
				`Invalid LUT content: expected ${maxDataRows} color rows for LUT_3D_SIZE ${size}, but got more`,
			);
		}

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