remotion-dev/remotion · error · Error

The config format has changed. Change…

Error message

The config format has changed. Change `Config.Rendering.*()` calls to `Config.*()` in your config file.

What it means

`Config.Rendering` was the pre-flat-config namespace for rendering-related setters. In the current flat `Config` object the `Rendering` getter throws immediately on access so stale config files fail loudly instead of silently no-op'ing.

Solutions

Move the call to the flat surface: `Config.setConcurrency(...)`.
Re-check the v3→v4 migration notes for the full list of moved setters and apply them all at once.

Example fix

// before
Config.Rendering.setConcurrency(2);
// after
Config.setConcurrency(2);

Defensive patterns

Strategy: validation

Validate before calling

const src = readFileSync('remotion.config.ts', 'utf8');
if (/Config\.Rendering\./.test(src)) {
  throw new Error('Remove Config.Rendering.* calls; use flat Config.* setters.');
}

Prevention

After every major upgrade, grep the config for any `Config.<Namespace>.` access.
Keep a single config file under test so removals surface in CI.

When it happens

Trigger: A remotion config file containing `Config.Rendering.setConcurrency(...)` (or any `Config.Rendering.*`) loaded against Remotion 4.x+/5.x.

Common situations: Post-upgrade config that was never migrated; vendored example config copied from an old Remotion version; IDE autocomplete suggesting the old namespace from cached type defs.

Related errors

AI-assisted analysis of remotion-dev/remotion@b2f4e34732 (2026-08-12). Data as JSON: /api/errors/1223fac610e9bd45. Report an issue: GitHub.

Appendix: source

Thrown at packages/cli/src/config/index.ts:757

		Puppeteer: void;
		/**
		 * @deprecated 'The config format has changed. Change `Config.Rendering.*()` calls to `Config.*()` in your config file.'
		 */
		Rendering: void;
		/**
		 * @deprecated 'The config format has changed. Change `Config.Output.*()` calls to `Config.*()` in your config file.'
		 */
		Output: void;
	};

export const Config: FlatConfig = {
	get Bundling() {
		throw new Error(
			'The config format has changed. Change `Config.Bundling.*()` calls to `Config.*()` in your config file.',
		);
	},
	get Rendering() {
		throw new Error(
			'The config format has changed. Change `Config.Rendering.*()` calls to `Config.*()` in your config file.',
		);
	},
	get Output() {
		throw new Error(
			'The config format has changed. Change `Config.Output.*()` calls to `Config.*()` in your config file.',
		);
	},
	get Log() {
		throw new Error(
			'The config format has changed. Change `Config.Log.*()` calls to `Config.*()` in your config file.',
		);
	},
	get Preview() {
		throw new Error(
			'The config format has changed. Change `Config.Preview.*()` calls to `Config.*()` in your config file.',
		);
	},

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