remotion-dev/remotion · error · Error

MPEG Layer I is not supported

Error message

MPEG Layer I is not supported

What it means

Thrown by `getMpegFrameLength` / `getUnroundedMpegFrameLength` when the MPEG audio layer is `1` (MPEG Layer I). The library explicitly supports only Layer II and Layer III (the common MP3 layers); Layer I uses a different frame structure and is unsupported.

Source

Thrown at packages/media-parser/src/containers/mp3/get-frame-length.ts:15

const getUnroundedMpegFrameLength = ({
	samplesPerFrame,
	bitrateKbit,
	samplingFrequency,
	padding,
	layer,
}: {
	samplesPerFrame: number;
	bitrateKbit: number;
	samplingFrequency: number;
	padding: boolean;
	layer: number;
}) => {
	if (layer === 1) {
		throw new Error('MPEG Layer I is not supported');
	}

	return (
		(((samplesPerFrame / 8) * bitrateKbit) / samplingFrequency) * 1000 +
		(padding ? (layer === 1 ? 4 : 1) : 0)
	);
};

export const getAverageMpegFrameLength = ({
	samplesPerFrame,
	bitrateKbit,
	samplingFrequency,
	layer,
}: {
	samplesPerFrame: number;
	bitrateKbit: number;
	samplingFrequency: number;
	layer: number;

View on GitHub (pinned to 78fe4bb3fd)

Solutions

1. Convert the audio file to MP3 (MPEG Layer III) using a tool like `ffmpeg`: `ffmpeg -i input.mp1 -codec:a libmp3lame output.mp3`.
2. Use a different audio format (AAC/M4A, WAV, Ogg) that `@remotion/media-parser` fully supports.
3. Verify the file is genuinely Layer III MP3 and not mislabeled.
4. If Layer I support is critical, report the file at remotion.dev/report.

Example fix

# convert Layer I to MP3 Layer III
ffmpeg -i input.mp1 -codec:a libmp3lame -qscale:a 2 output.mp3

// Check file type before parsing
import {parseFile} from 'music-metadata'; // or ffprobe

async function isLayer3Mp3(file: File): Promise<boolean> {
  // Use ffprobe or a metadata library to check the MPEG layer
  // If layer is I, reject before calling parseMedia
  return true; // implement with your preferred tool
}

try {
  await parseMedia({src, fields: {durationInSeconds: true}});
} catch (e) {
  if (e instanceof Error && e.message === 'MPEG Layer I is not supported') {
    console.error('This is an MPEG Layer I file. Convert to Layer III MP3 or AAC.');
  }
  throw e;
}

When it happens

Trigger: Parsing an MPEG audio file whose frame header indicates Layer I (`layerBits === 0b11`). This can be reached during frame-length calculation in `get-frame-length.ts:14-16` or `parse-packet-header.ts` via `getMpegFrameLength`.

Common situations: Files with the `.mp1` extension or MPEG Layer I audio. Old `.mpa` or `.mpg` files from legacy MPEG-1 systems. Misidentified files that are labeled `.mp3` but are actually Layer I encoded.

Related errors

• MP3 files with VBRI are currently unsupported because we hav
• Free bitrate not supported
• Unsupported audio format ${strf.formatTag}
• Unexpected audio object type ${audioObjectType}
• Only supporting MPEG-4 for .aac

AI-assisted analysis of remotion-dev/remotion@78fe4bb3fd (2026-08-12). Data as JSON: /api/errors/0e821c0b4d96cb36. Report an issue: GitHub.