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Speech synthesis in WAV format using the API v1

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Updated at February 10, 2025

The example shows how you can use the API v1 to synthesize speech from text in TTS markup to a WAV file.

The example uses the following synthesis parameters:

  • Synthesized audio file format: LPCM with a sample rate of 48,000 Hz, WAV container.
  • Language: Russian
  • Voice: filipp

Conversion and recording the result in WAV are performed using the SoX utility.

The Yandex account or federated account are authenticated using an IAM token. If using a service account, you do not need to include the folder ID in the request. To learn more about SpeechKit API authentication, see Authentication with the SpeechKit API.

  1. Synthesize a file in LPCM format:

    Submit a text-to-speech conversion request:

    read -r -d '' TEXT << EOM
> I'm Yandex Speech+Kit.
> I can turn any text into speech.
> Now y+ou can, too!
EOM
export FOLDER_ID=<folder_ID>
export IAM_TOKEN=<IAM_token>
curl \
  --request POST \
  --header "Authorization: Bearer ${IAM_TOKEN}" \
  --output speech.raw \
  --data-urlencode "text=${TEXT}" \
  --data "lang=ru-RU&voice=filipp&folderId=${FOLDER_ID}&format=lpcm&sampleRateHertz=48000" \
  https://tts.api.cloud.yandex.net/speech/v1/tts:synthesize

    Where:

    Submit a text-to-speech conversion request:

    using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Threading.Tasks;
using System.IO;

namespace TTS
{
  class Program
  {
    static void Main()
    {
      Tts().GetAwaiter().GetResult();
    }

    static async Task Tts()
    {
      const string iamToken = "<IAM_token>";
      const string folderId = "<folder_ID>";

      HttpClient client = new HttpClient();
      client.DefaultRequestHeaders.Add("Authorization", "Bearer " + iamToken);
      var values = new Dictionary<string, string>
      {
        { "text", "I'm Yandex Speech+Kit. I can turn any text into speech. Now y+ou can, too!" },
        { "lang", "ru-RU" },
        { "voice", "filipp" },
        { "folderId", folderId },
        { "format", "lpcm" },
        { "sampleRateHertz", "48000" }
      };
      var content = new FormUrlEncodedContent(values);
      var response = await client.PostAsync("https://tts.api.cloud.yandex.net/speech/v1/tts:synthesize", content);
      var responseBytes = await response.Content.ReadAsByteArrayAsync();
      File.WriteAllBytes("speech.raw", responseBytes);
    }
  }
}

    Where:

    • Create a file (e.g., test.py), and add the following code to it:

      import argparse
import requests

def synthesize(folder_id, iam_token, text):
    url = 'https://tts.api.cloud.yandex.net/speech/v1/tts:synthesize'
    headers = {
        'Authorization': 'Bearer ' + iam_token,
    }

    data = {
        'text': text,
        'lang': 'ru-RU',
        'voice': 'filipp',
        'folderId': folder_id,
        'format': 'lpcm',
        'sampleRateHertz': 48000,
    }

    with requests.post(url, headers=headers, data=data, stream=True) as resp:
        if resp.status_code != 200:
            raise RuntimeError("Invalid response received: code: %d, message: %s" % (resp.status_code, resp.text))

        for chunk in resp.iter_content(chunk_size=None):
            yield chunk


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("--token", required=True, help="IAM token")
    parser.add_argument("--folder_id", required=True, help="Folder id")
    parser.add_argument("--text", required=True, help="Text for synthesize")
    parser.add_argument("--output", required=True, help="Output file name")
    args = parser.parse_args()

    with open(args.output, "wb") as f:
        for audio_content in synthesize(args.folder_id, args.token, args.text):
            f.write(audio_content)

      Where:

      • lang: Text language.
      • voice: Voice for speech synthesis.
      • format: Synthesized audio file format.
      • sampleRateHertz: Sample rate of the LPCM audio file.

    • Run the created file:

      export FOLDER_ID=<folder_ID>
export IAM_TOKEN=<IAM_token>
python3 test.py
  --token ${IAM_TOKEN}
  --folder_id ${FOLDER_ID}
  --output speech.raw
  --text "I'm Yandex Speech+Kit. I can turn any text into speech. Now y+ou can, too!"

      Where:

    Submit a text-to-speech conversion request:

    <?php

$token = '<IAM_token>'; # Specify an IAM token.
$folderId = "<folder_ID>"; #: Specify a folder ID.

$url = "https://tts.api.cloud.yandex.net/speech/v1/tts:synthesize";
$headers = ['Authorization: Bearer ' . $token];
$post = array(
    'text' => "I'm Yandex Speech+Kit. I can turn any text into speech. Now y+ou can, too!",
    'folderId' => $folderId,
    'lang' => 'ru-RU',
    'voice' => 'filipp',
    'format' => 'lpcm',
    'sampleRateHertz' => '48000');

$ch = curl_init();

curl_setopt($ch, CURLOPT_AUTOREFERER, TRUE);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE);
curl_setopt($ch, CURLOPT_HEADER, false);
if ($post !== false) {
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $post);
}
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

$response = curl_exec($ch);
if (curl_errno($ch)) {
    print "Error: " . curl_error($ch);
}
if (curl_getinfo($ch, CURLINFO_HTTP_CODE) != 200) {
    $decodedResponse = json_decode($response, true);
    echo "Error code: " . $decodedResponse["error_code"] . "\r\n";
    echo "Error message: " . $decodedResponse["error_message"] . "\r\n";
} else {
    file_put_contents("speech.raw", $response);
}
curl_close($ch);

    Where:

  2. Convert the resulting file to WAV format using the SoX utility.

    sox -r 48000 -b 16 -e signed-integer -c 1 speech.raw speech.wav

See also

Previous
Brand Voice Call Center pattern-based speech synthesis
Next
Speech synthesis in OggOpus format, API v1