stt (Speech-To-Text)

Overview

CLOVA Speech Recognition (CSR) API is an HTTP based REST API that gets audio input in the specified language and returns the result of the speech recognition as text.
The supported input speech data formats are MP3, AAC, AC3, OGG, FLAC, and WAV.

Request

Request Parameters

Request Header

Request Body

Response

Response Body

Examples

Request Example

[HTTP Request URL]
https://naveropenapi.apigw.ntruss.com/recog/v1/stt?lang=Kor

[HTTP Request Body]
--- binary sound data ---

Request Example

{
  "text": "Hello"
}

API examples

This section provides code examples of using the CSR API for each language.

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;

public class Main {

    public static void main(String[] args) {
        String clientId = "YOUR_CLIENT_ID";             // Application Client ID";
        String clientSecret = "YOUR_CLIENT_SECRET";     // Application Client Secret";

        try {
            String imgFile = "Speech file path";
            File voiceFile = new File(imgFile);

            String language = "Kor";        // Language code (Kor, Jpn, Eng, Chn)
            String apiURL = "https://naveropenapi.apigw.ntruss.com/recog/v1/stt?lang=" + language;
            URL url = new URL(apiURL);

            HttpURLConnection conn = (HttpURLConnection)url.openConnection();
            conn.setUseCaches(false);
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.setRequestProperty("Content-Type", "application/octet-stream");
            conn.setRequestProperty("X-NCP-APIGW-API-KEY-ID", clientId);
            conn.setRequestProperty("X-NCP-APIGW-API-KEY", clientSecret);

            OutputStream outputStream = conn.getOutputStream();
            FileInputStream inputStream = new FileInputStream(voiceFile);
            byte[] buffer = new byte[4096];
            int bytesRead = -1;
            while ((bytesRead = inputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, bytesRead);
            }
            outputStream.flush();
            inputStream.close();
            BufferedReader br = null;
            int responseCode = conn.getResponseCode();
            if(responseCode == 200) { // Normal
                br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            } else { // Error occurred.
                System.out.println("error!!!!!!! responseCode= " + responseCode);
                br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            }
            String inputLine;

            if(br != null) {
                StringBuffer response = new StringBuffer();
                while ((inputLine = br.readLine()) != null) {
                    response.append(inputLine);
                }
                br.close();
                System.out.println(response.toString());
            } else {
                System.out.println("error !!!");
            }
        } catch (Exception e) {
            System.out.println(e);
        }
    }
}

<?php

$curl = curl_init();
$file_path = "Speech file path";

$lang = "Kor";  // Language code (Kor, Jpn, Eng, Chn)
$client_id = "YOUR_CLIENT_KEY";
$client_secret = "YOUR_CLIENT_SECRET";

curl_setopt_array($curl, array(
  CURLOPT_URL => "https://naveropenapi.apigw.ntruss.com/recog/v1/stt?lang=".$lang,
  CURLOPT_RETURNTRANSFER => 1,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_POST => 1,
  CURLOPT_POSTFIELDS => file_get_contents($file_path),
  CURLOPT_HTTPHEADER => array(
    "Content-Type: application/octet-stream",
    "X-NCP-APIGW-API-KEY-ID: ".$client_id,
    "X-NCP-APIGW-API-KEY: ".$client_secret
  ),
));

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

?>

const fs = require('fs');
const request = require('request');

const clientId = 'YOUR_CLIENT_ID';
const clientSecret = 'YOUR_CLIENT_SECRET';

// language => Language code (Kor, Jpn, Eng, Chn)
function stt(language, filePath) {
    const url = `https://naveropenapi.apigw.ntruss.com/recog/v1/stt?lang=${language}`;
    const requestConfig = {
        url: url,
        method: 'POST',
        headers: {
            'Content-Type': 'application/octet-stream',
            'X-NCP-APIGW-API-KEY-ID': clientId,
            'X-NCP-APIGW-API-KEY': clientSecret
        },
        body: fs.createReadStream(filePath)
    };

    request(requestConfig, (err, response, body) => {
        if (err) {
            console.log(err);
            return;
        }

        console.log(response.statusCode);
        console.log(body);
    });
}

stt('Kor', 'Speech file path (ex: ./test.wav)');

import sys
import requests
client_id = "YOUR_CLIENT_ID"
client_secret = "YOUR_CLIENT_SECRET"
lang = "Kor" # Language code (Kor, Jpn, Eng, Chn)
url = "https://naveropenapi.apigw.ntruss.com/recog/v1/stt?lang=" + lang
data = open('Speech file path', 'rb')
headers = {
    "X-NCP-APIGW-API-KEY-ID": client_id,
    "X-NCP-APIGW-API-KEY": client_secret,
    "Content-Type": "application/octet-stream"
}
response = requests.post(url,  data=data, headers=headers)
rescode = response.status_code
if(rescode == 200):
    print (response.text)
else:
    print("Error : " + response.text)

using System;
using System.Net;
using System.Text;
using System.IO;
using System.Collections.Generic;
using System.Collections.Specialized;

namespace NaverAPI_Guide
{
    class APIExamSTT
    {
        static void Main(string[] args)
        {
            string FilePath = "YOUR_FILE_NAME";
            FileStream fs = new FileStream(FilePath, FileMode.Open, FileAccess.Read);
            byte[] fileData = new byte[fs.Length];
            fs.Read(fileData, 0, fileData.Length);
            fs.Close();

            string lang = "Kor";        // Language code (Kor, Jpn, Eng, Chn)
            string url = $"https://naveropenapi.apigw.ntruss.com/recog/v1/stt?lang={lang}";
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Headers.Add("X-NCP-APIGW-API-KEY-ID", "YOUR_CLIENT_ID");
            request.Headers.Add("X-NCP-APIGW-API-KEY", "YOUR_CLIENT_SECRET");
            request.Method = "POST";
            request.ContentType = "application/octet-stream";
            request.ContentLength = fileData.Length;
            using (Stream requestStream = request.GetRequestStream())
            {
                requestStream.Write(fileData, 0, fileData.Length);
                requestStream.Close();
            }
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream stream = response.GetResponseStream();
            StreamReader reader = new StreamReader(stream, Encoding.UTF8);
            string text = reader.ReadToEnd();
            stream.Close();
            response.Close();
            reader.Close();
            Console.WriteLine(text);
        }
    }
}

Error Codes