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Speaker diarization

Enable diarization to identify who is speaking when. If you know the expected speaker count, pass min_speakers and max_speakers to improve accuracy.
Example response with diarization:

Word-level timestamps

Get word-level timing information:
Example output:
Text

Response formats

JSON format (default)

Returns only the transcribed/translated text:

Verbose JSON format

Returns detailed information including timestamps:
Example output:
Text

Advanced features

Temperature control

Adjust randomness in the output (0.0 = deterministic, 1.0 = creative):

Async support

All transcription and translation operations support async/await:

Async transcription

Async translation

Concurrent processing

Process multiple audio files concurrently:

Best practices

Choose the right method

  • Batch transcription: Best for pre-recorded audio files, podcasts, or any non-real-time use case.
  • Real-time streaming: Best for live conversations, voice assistants, or applications requiring immediate feedback.

Audio quality tips

  • Use high-quality audio files for better transcription accuracy.
  • Minimize background noise.
  • Ensure clear speech with good volume levels.
  • Use appropriate sample rates (16kHz or higher recommended).
  • For WebSocket streaming, use PCM format: pcm_s16le_16000.
  • Direct uploads are capped at 500 MB of audio per request, while URL uploads are capped at 1 GB or 4 hours of audio per request. See Limits.
  • For binary uploads, place the model form field before the file field in the multipart body so the server can route the request without buffering the audio.
  • For long audio files (over 4 hours), chunk the audio into ≤ 4 h segments and send each chunk as a separate URL request.
  • Use streaming for real-time applications when available.

Diarization best practices

  • Works best with clear audio and distinct speakers.
  • Speakers are labeled as SPEAKER_00, SPEAKER_01, etc.
  • Use with verbose_json format to get segment-level speaker information.

Errors and troubleshooting

Next steps