如何使用Text-to-Speech服务将Watson语音通过管道传输到浏览器

Question

I have an express application and I added this snippet of code:

var TextToSpeechV1 = require('watson-developer-cloud/text-to-speech/v1');
var fs = require('fs');

var text_to_speech = new TextToSpeechV1({
  username: '<username>', (added username and password)
  password: '<password>'
});

var params = {
  text: 'Hello from IBM Watson',
  voice: 'en-US_AllisonVoice', // Optional voice
  accept: 'audio/wav'
};

// Pipe the synthesized text to a file
text_to_speech.synthesize(params).pipe(fs.createWriteStream('output.wav'));

After running the node app command, a ouput.wav was generated in my file. It worked as expected and said "Hello from IBM Watson." But I want this to be outputted to the browser, like when someone presses a tag. How do I go from here?

Answer 1

The Text to Speech demo does what you want and it's on GitHub . It streams the audio back to the Browser which uses an <audio> HTML tag to reproduce it.

If yo useparate your application in Client and Server you will need:

Client

An <audio> element with the src pointing to an endpoint that synthesizes the text, something like: https://<host>/api/synthesize?text=This+is+a+test

Server

Assuming you use Express and based on your code above

app.get('/api/synthesize', function(req, res, next) {
  var transcript = text_to_speech.synthesize(req.query);
  transcript.on('error', next);
  transcript.pipe(res);
});

The audio will be pipe to the browser which will play it as it comes from the service.