Pre-recorded Audio

Sample Rate Requirements

The API accepts a range of sample rates. Files at other rates are automatically resampled.

Supported sample rates

Sample RateUse CaseNotes
8,000 HzTelephony (PSTN, IVR)Standard for call center recordings.
16,000 HzGeneral purpose — recommendedBest balance of accuracy and file size.
22,050 HzBroadcast audioAccepted, resampled internally.
44,100 HzCD qualityAccepted, resampled internally.
48,000 HzProfessional / studioAccepted, resampled internally.
Best practice: Convert audio to 16kHz before sending. Use: ffmpeg -i input.wav -ar 16000 output.wav
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