Need to get audio file from twilio media stream

[mazaharulhq]

I am trying to get audio file from twilio media stream and later need to transcribe that audio from IBM watson. I followed https://stackoverflow.com/questions/58439005/is-there-any-way-to-save-mulaw-audio-stream-from-twilio-in-a-file thread and following npm package https://www.npmjs.com/package/twilio-media-stream-save-audio-file and was able to get wav file successfully but IBM watson complains about wrong file format.

Below is the code I used.

const WebSocket = require("ws");
const express = require("express");
const app = express();
const server = require("http").createServer(app);
const wss = new WebSocket.Server({ server });
const fs = require('fs');
const SpeechToTextV1 = require('ibm-watson/speech-to-text/v1');
const { base64encode, base64decode } = require('nodejs-base64');

const { IamAuthenticator } = require('ibm-watson/auth');
const TwilioMediaStreamSaveAudioFile = require("twilio-media-stream-save-audio-file");

const speechToText = new SpeechToTextV1({
authenticator: new IamAuthenticator({
apikey: 'Dummy*',
}),
serviceUrl: 'https://api.us-east.speech-to-text.watson.cloud.ibm.com/instances/****Dummy*****/v1/recognize/',
});

const mediaStreamSaver = new TwilioMediaStreamSaveAudioFile({
saveLocation: "C:\TwilioWavFiles\",
saveFilename: "my-twilio-media-stream-output",
onSaved: () =>
{
console.log("File was saved!")

    const params = {
      //objectMode: true,
     //contentType: 'audio/mulaw',
      rate:'8000',
      contentType: 'audio/wav',
      languageCustomizationId: '**** Dummy *****',
     // keywords: ['colorado', 'tornado', 'tornadoes'],
      grammarName:'name-grammar',
     // keywordsThreshold: 0.5,
     // maxAlternatives: 3,
    
    };

    const recognizeStream = speechToText.recognizeUsingWebSocket(params);

   // Pipe in the audio.
   fs.createReadStream('C:\\TwilioWavFiles\\my-twilio-media-stream-output.wav').pipe(recognizeStream);

 

   recognizeStream.pipe(fs.createWriteStream('transcription.txt'));

   recognizeStream.setEncoding('utf8');

   // Listen for events.

recognizeStream.on('data', function(event)
{
onEvent('Data:', event);
});
recognizeStream.on('error', function(event)
{
onEvent('Error:', event);
});

recognizeStream.on('close', function(event)
{
onEvent('Close:', event);
});

// Display events on the console.
function onEvent(name, event) {
console.log(name, JSON.stringify(event, null, 2));
};
}
});

// Handle Web Socket Connection
wss.on("connection", function connection(ws) {

console.log("New connection initiated!");
mediaStreamSaver.setWebsocket(ws);

ws.on("message", function incoming(message) {
const msg = JSON.parse(message);
// console.log("msg :: "+msg);
// console.log("message :: "+message);
switch (msg.event) {
case "connected":
console.log(A new call has connected.);
mediaStreamSaver.twilioStreamStart();
break;
case "start":
console.log(Starting Media Stream ${msg.streamSid});
break;
case "media":

    let decoded = base64decode(msg.media.payload);
    console.log("decoded  string is :: "+decoded);

    mediaStreamSaver.twilioStreamMedia(msg.media.payload);
    break;
  case "stop":
    console.log(`Call Has Ended`);
    mediaStreamSaver.twilioStreamStop();
    break;
}

});
});

//Handle HTTP Request
app.get("/", (req, res) => res.send("Hello World"));

app.post("/twiml", (req, res) => {
res.set("Content-Type", "text/xml");

res.send(<Response> <Start> <Stream url="wss://${req.headers.host} " /> </Start> <Say>Say your name </Say> <Pause length="5" /> </Response>);
});

console.log("Listening at Port 8080");
server.listen(8080);