remotion-dev/remotion · error · Error

Unsupported subformat: ${subFormat}

Error message

Unsupported subformat: ${subFormat}

What it means

For EXTENSIBLE WAVs the 16-byte subFormat GUID is tested against the PCM GUID and the IEEE-float GUID (subformatIsPcm / subformatIsIeeeFloat). If it matches neither, the parser does not know how to decode the samples and throws the raw GUID bytes. Only PCM and IEEE-float subtypes are modeled.

Source

Thrown at packages/media-parser/src/containers/wav/parse-fmt.ts:113

			);
		}

		iterator.getUint16Le(); // valid bits per sample
		const channelMask = iterator.getUint32Le();
		const subFormat = iterator.getSlice(16);
		// check if same as [ 1, 0, 0, 0, 0, 0, 16, 0, 128, 0, 0, 170, 0, 56, 155, 113 ]
		if (subFormat.length !== 16) {
			throw new Error(
				`Only supporting WAVE with PCM audio format, but got ${subFormat.length}`,
			);
		}

		if (subformatIsPcm(subFormat)) {
			// is pcm
		} else if (subformatIsIeeeFloat(subFormat)) {
			// is ieee float
		} else {
			throw new Error(`Unsupported subformat: ${subFormat}`);
		}

		const channels = getChannelsFromMask(channelMask);
		wavHeader.numberOfChannels = channels.length;
	}

	await registerAudioTrack({
		track: {
			type: 'audio',
			codec: format,
			codecData: null,
			description: undefined,
			codecEnum: format,
			numberOfChannels,
			sampleRate,
			originalTimescale: 1_000_000,
			trackId: 0,
			startInSeconds: 0,

View on GitHub (pinned to 78fe4bb3fd)

Solutions

1. Identify the underlying codec with ffprobe.
2. Re-encode to PCM: ffmpeg -i in.wav -c:a pcm_s16le out.wav.
3. Use Mediabunny for wider GUID/codec handling.
4. try/catch parseMedia() and skip the file.

Example fix

# unknown subFormat GUID -> PCM
ffmpeg -i in.wav -c:a pcm_s16le out.wav

await parseMedia({ src: 'out.wav' });

// confirm the subFormat is PCM or IEEE float via ffprobe codec_name
// ffprobe -show_entries stream=codec_name in.wav

const SUPPORTED_SUBFORMATS = new Set(['pcm_s16le','pcm_s24le','pcm_s32le','pcm_f32le']);
const isSupportedSubformat = (codec: string) => SUPPORTED_SUBFORMATS.has(codec);

try {
  await parseMedia({ src: 'in.wav' });
} catch (err) {
  if (err instanceof Error && /Unsupported subformat/i.test(err.message)) {
    // unknown GUID — re-encode to PCM or skip
  } else throw err;
}

When it happens

Trigger: A WAVE_FORMAT_EXTENSIBLE WAV whose subFormat GUID is neither KSDATAFORMAT_SUBTYPE_PCM nor the IEEE-float subtype — e.g. ADPCM, A-law, μ-law, WMA, or another codec wrapped in the EXTENSIBLE format.

Common situations: Compressed audio wrapped in WAVE_FORMAT_EXTENSIBLE; proprietary/legacy codec GUIDs; DAW exports of unusual codecs.

Related errors

• Only supporting WAVE with PCM audio format, but got ${audioF
• Unsupported bits per sample: ${bitsPerSample}
• Unexpected sampling frequency index ${samplingFrequencyIndex
• Unexpected sample rate ${sampleRate}
• Unexpected audio object type ${audioObjectType}

AI-assisted analysis of remotion-dev/remotion@78fe4bb3fd (2026-08-12). Data as JSON: /api/errors/da2ffee1e0fbfc1e. Report an issue: GitHub.