How to choose audio formats

Input formats

The ref_audio file accepts the following codecs:

For best cloning quality, use WAV or FLAC. Telephony codecs (MULAW, ALAW) work but cap the achievable fidelity at the source.

Output formats

Specify the output codec via output_audio_codec. The default is wav.

Sample rate

Use speech_sample_rate to set the output sample rate in Hz:

8000, 16000, 22050, 24000, 32000, 44100, 48000

If omitted, the API returns audio at the model’s native rate (24,000 Hz). Set the sample rate to match your downstream pipeline:

File size guidance

Higher sample rates and uncompressed codecs produce larger output files. As a rough guide for a 10-second clip:

For high-volume API usage, choose a compressed codec (mp3, opus, aac) unless your downstream pipeline specifically requires uncompressed audio.

Decoding the response

The audio field is a base64-encoded string of the raw bytes for the codec you requested. Decode it and write it to a file with the appropriate extension:

curl -s -X POST "https://api.sarvam.ai/voices/clone" \
  -H "api-subscription-key: $SARVAM_API_KEY" \
  -F "text=Hello world" \
  -F "language_code=en-IN" \
  -F "ref_audio=@reference.wav" \
  -F "output_audio_codec=wav" \
  -o response.json
# Decode audio into a file; use the extension matching your output_audio_codec
python3 -c "import base64, json; open('output.wav', 'wb').write(base64.b64decode(json.load(open('response.json'))['audio']))"

import fs from "fs";
const form = new FormData();
form.append("text", "Hello world");
form.append("language_code", "en-IN");
form.append("output_audio_codec", "wav");
form.append("ref_audio", new Blob([fs.readFileSync("reference.wav")]), "reference.wav");
const response = await fetch("https://api.sarvam.ai/voices/clone", {
  method: "POST",
  headers: { "api-subscription-key": process.env.SARVAM_API_KEY },
  body: form,
});
const result = await response.json();
if (!response.ok) {
  console.error(`Voice cloning failed (${response.status}):`, result.error?.message);
  process.exit(1);
}
const audioBytes = Buffer.from(result.audio, "base64");
fs.writeFileSync("output.wav", audioBytes);

Next steps