danny-avila/LibreChat · warning

The audio file format

Error message

The audio file format ${rawFormat} is not accepted

What it means

azureOpenAIProvider accepts only flac, mp3, mp4, mpeg, mpga, m4a, ogg, wav, webm. It first normalizes the upload's MIME through MIME_TO_EXTENSION_MAP; if not mapped, it falls back to the subtype after the `/`. If neither result is in acceptedFormats, it throws with the offending subtype.

Solutions

1. Transcode the file to an accepted format (mp3, wav, ogg, or webm) before upload.
2. Ensure the upload's Content-Type/mimetype is correct for the actual bytes.
3. Only if a mapped format is genuinely supported by your deployment, extend MIME_TO_EXTENSION_MAP to normalize it into an accepted extension.

Example fix

// before: send audio/aac directly
// after: transcode to mp3 before upload (ffmpeg)
// ffmpeg -i input.aac -codec:a libmp3lame output.mp3

const ACCEPTED = ['flac','mp3','mp4','mpeg','mpga','m4a','ogg','wav','webm'];
const [, raw = ''] = audioFile.mimetype.split('/');
if (!ACCEPTED.includes(rawFormat)) {
  return res.status(415).json({ error: `Unsupported audio format: ${rawFormat}` });
}

When it happens

Trigger: Upload audio whose normalized extension and raw subtype are both outside the allowlist — e.g. audio/aac, audio/x-aiff, audio/ac3, video/quicktime.

Common situations: Browser reports an uncommon MIME; recorder produces AAC/AIFF; multer/file-type detection mislabels the file; user uploads a container the provider doesn't support.

Related errors

• The audio file size exceeds the limit of 25MB
• Could not determine file extension from MIME type
• Failed to convert base64 to buffer
• File embedding failed. The filetype
• Invalid avatar URL

AI-assisted analysis of danny-avila/LibreChat@5ff282f900 (2026-08-12). Data as JSON: /api/errors/bdb05b6457b36729. Report an issue: GitHub.

Appendix: source

Thrown at api/server/services/Files/Audio/STTService.js:255

      azureOpenAIApiDeploymentName: extractEnvVariable(sttSchema?.deploymentName),
    })}/audio/transcriptions?api-version=${extractEnvVariable(sttSchema?.apiVersion)}`;

    const apiKey = sttSchema.apiKey ? resolveConfigSecret(sttSchema.apiKey) || '' : '';

    if (audioBuffer.byteLength > 25 * 1024 * 1024) {
      throw new Error('The audio file size exceeds the limit of 25MB');
    }

    const acceptedFormats = ['flac', 'mp3', 'mp4', 'mpeg', 'mpga', 'm4a', 'ogg', 'wav', 'webm'];
    const [mimePrefix, rawFormat = ''] = audioFile.mimetype.split('/');
    const isAudioMime = mimePrefix === 'audio' || mimePrefix === 'video';
    const isKnownMime = audioFile.mimetype in MIME_TO_EXTENSION_MAP;
    const normalizedFormat = isKnownMime ? MIME_TO_EXTENSION_MAP[audioFile.mimetype] : null;
    if (
      !acceptedFormats.includes(normalizedFormat) &&
      !(isAudioMime && acceptedFormats.includes(rawFormat))
    ) {
      throw new Error(`The audio file format ${rawFormat} is not accepted`);
    }

    const formData = new FormData();
    formData.append('file', audioBuffer, {
      filename: audioFile.originalname,
      contentType: audioFile.mimetype,
    });

    const validLanguage = getValidatedLanguageCode(language);
    if (validLanguage) {
      formData.append('language', validLanguage);
    }

    const headers = {
      ...(apiKey && { 'api-key': apiKey }),
    };

    [headers].forEach(this.removeUndefined);

View on GitHub (pinned to 5ff282f900)