remotion-dev/remotion · error · Error

MP3 files with VBRI are currently unsupported because we hav

Error message

MP3 files with VBRI are currently unsupported because we have no sample file. Submit this file at remotion.dev/report if you would like us to support this file.

What it means

Thrown when an MP3 file's first frame contains a `VBRI` header (the Fraunhofer Encoder variable-bitrate format). The library currently supports only Xing headers for VBR detection and has no sample VBRI file to implement or test against, so it explicitly rejects these files with a request to submit them.

Source

Thrown at packages/media-parser/src/containers/mp3/parse-mpeg-header.ts:57

			throw new Error(
				`Bitrate mismatch at offset ${initialOffset}: ${bitrateInKbit} !== ${cbrMp3Info.bitrateInKbit}`,
			);
		}
	}

	const offsetNow = iterator.counter.getOffset();
	iterator.counter.decrement(offsetNow - initialOffset);
	const data = iterator.getSlice(frameLength);

	if (state.callbacks.tracks.getTracks().length === 0) {
		const info: Mp3Info = {
			layer,
			mpegVersion,
			sampleRate,
		};
		const asText = new TextDecoder().decode(data);
		if (asText.includes('VBRI')) {
			throw new Error(
				'MP3 files with VBRI are currently unsupported because we have no sample file. Submit this file at remotion.dev/report if you would like us to support this file.',
			);
		}

		if (asText.includes('Info')) {
			return;
		}

		const isVbr = asText.includes('Xing');
		if (isVbr) {
			const xingData = parseXing(data);
			Log.verbose(
				state.logLevel,
				'MP3 has variable bit rate. Requiring whole file to be read',
			);
			state.mp3.setMp3BitrateInfo({
				type: 'variable',
				xingData,

View on GitHub (pinned to 78fe4bb3fd)

Solutions

Re-encode the MP3 using LAME or ffmpeg so it uses a Xing header instead of VBRI: `ffmpeg -i input.mp3 -codec:a libmp3lame -qscale:a 2 output.mp3`.
Convert the file to a different supported format (AAC/M4A, WAV, Ogg Vorbis).
Submit the file at remotion.dev/report so the library can add VBRI support.
Use an alternative media parsing library that supports VBRI headers.

Example fix

# re-encode to replace VBRI with Xing header
ffmpeg -i input.mp3 -codec:a libmp3lame -qscale:a 2 output.mp3

Defensive patterns

Strategy: try-catch

Validate before calling

// Check for VBRI header before parsing
async function hasVbriNotXing(file: File): Promise<boolean> {
  const buf = await file.slice(0, 4096).arrayBuffer();
  const text = new TextDecoder().decode(new Uint8Array(buf));
  return text.includes('VBRI') && !text.includes('Xing');
}

Try / catch

try {
  await parseMedia({src, fields: {durationInSeconds: true}});
} catch (e) {
  if (e instanceof Error && e.message.includes('VBRI')) {
    console.error('VBRI VBR MP3 is unsupported. Re-encode with LAME/ffmpeg.');
  }
  throw e;
}

Prevention

Re-encode MP3 files with LAME or ffmpeg to replace VBRI headers with Xing.
Use ffmpeg -i input.mp3 -codec:a libmp3lame -qscale:a 2 output.mp3.
If VBRI is from the Fraunhofer encoder, switch to a LAME-based encoder.
Submit VBRI files at remotion.dev/report to help add support.

When it happens

Trigger: During first-frame parsing in `parseMpegHeader`, the decoded frame text includes the string `'VBRI'` (checked at `parse-mpeg-header.ts:56`). This indicates the file uses the Fraunhofer VBR header format rather than the Xing format the parser supports.

Common situations: MP3 files produced by the Fraunhofer encoder or certain older professional audio tools. Files exported from specific DAWs or broadcasting software that default to VBRI. Rare in consumer-grade encoders like LAME (which use Xing).

Related errors

AI-assisted analysis of remotion-dev/remotion@78fe4bb3fd (2026-08-12). Data as JSON: /api/errors/c05b83736e730e5a. Report an issue: GitHub.