Bing Speech-To-Text and Text-To-Speech Client JavaScript Lib

A small JavaScript library to call Bing Speech-To-Text API with continuous voice detection and Text-To-Speech API

This library fixes a couple of issues currently exposed in the official SDK: https://github.com/Microsoft/Cognitive-Speech-STT-JavaScript such as:

• reusing the web audio context that will be instanced one to avoid breaking in Chrome after 6 calls
• continuous recognition by detecting the voice/silence and automatically sending the audio sample to the API for analyze
• reusing the authentication token as it's valid for 10 min rather than creating it again on each request for better performance
• better browsers compatibility (specifically with Firefox and Chrome, or mobile Safari for Web Audio)

However, it doesn't support NACL or ActiveX fallbacks for older browsers such as IE11 or older versions of Chrome.

Prerequisites

• For Text-To-Speech, you need a Web Audio compatible browser to use this library (MS Edge, Chrome, Safari, Firefox or Opera) and it needs also to support ES6/ES2015: http://kangax.github.io/compat-table/es6/.
• For Speech-To-Text, you need a GetUserMedia and Web Audio compatible browser to use this library (MS Edge, Chrome, Firefox or Opera).
• Reference BingSpeech.js in your HTML page.
• Generate your Bing Speech API key:
  • Free: https://www.microsoft.com/cognitive-services/en-us/subscriptions?productId=/products/Bing.Speech.Preview
  • Paid: https://portal.azure.com/#create/Microsoft.CognitiveServices/apitype/Bing.Speech/pricingtier/S0

Usage for Speech-To-Text

Constructor

// By default, it will use en-us
var bingClientRecognition = new BingSpeech.RecognitionClient("YOUR_BING_SPEECH_API_KEY");

// You can change it
var bingClientRecognition = new BingSpeech.RecognitionClient("YOUR_BING_SPEECH_API_KEY ", "fr-fr");

Supported locales can be found here: https://www.microsoft.com/cognitive-services/en-us/Speech-api/documentation/API-Reference-REST/BingVoiceRecognition

Available Events

Before starting the microphone and the continuous recognition process, you must first take care of the various events available.

Those 4 events could be useful to notify the user that something is going on:

• onVoiceDetected() is raised when the library has detected a voice and started to record the audio sample from your microphone.
• onVoiceEnded() when the library has detected the end of the speech, it will then send the recorded audio to Bing Speech API for recognition.
• onNetworkActivityStarted() when the audio sample is currently being sent via the network to Bing Speech API.
• onNetworkActivityEnded() when all network requests have finished.

The 2 others events are more important as this is the way to get the answer:

• onFinalResponseReceived(text) will be called as soon as the Bing Speech API have been able to recognize an audio sample received. It will return the associated text.
• onError(code, requestId) will be raised in case of errors. The code will be the HTTP error code if available and the requestId could help you troubleshooting which request failed using a F12 network tab tool. Several possible cases of errors;
  • the audio sample sent contains no interesting text to be recognized like background noise.
  • classic HTTP error like 5xx.
  • you've reached the quota of number of requests / min (20 for the free key) and the error 429 will be raised.

Start the recognition process

bingClientRecognition.startMicAndContinuousRecognition();

Stop the recognition process

bingClientRecognition.endMicAndContinuousRecognition();

Please check the sample available in the SpeechToTextSample directory for a complete usage.

Using logic extracted from https://github.com/mattdiamond/Recorderjs for the WAV encoding and https://github.com/kdavis-mozilla/vad.js for the Voice activity detection in JavaScript.

Usage for Text-To-Speech

Constructor

// By default, it will use EN-US Male voice/locale
var bingClientTTS = new BingSpeech.TTSClient("YOUR_BING_SPEECH_API_KEY");

// You can change it
var bingClientTTS = new BingSpeech.TTSClient("YOUR_BING_SPEECH_API_KEY ", BingSpeech.SupportedLocales.frFR_Male);

Speech with synthesize()

// Use the synthesize function to speech, it will use the locale set in the constructor by default
// For instance, this will use the EN-US male voice/locale on both sentences
var bingClientTTS = new BingSpeech.TTSClient("YOUR_BING_SPEECH_API_KEY ");
bingClientTTS.synthesize("Hello, my name is Mat, I'm glad to meet you.");
bingClientTTS.synthesize("How are you?");

Overriding locale

// But you can override it anytime like that
var bingClientTTS = new BingSpeech.TTSClient("YOUR_BING_SPEECH_API_KEY ");
bingClientTTS.synthesize("Hello, my name is Mat.");
bingClientTTS.synthesize("Salut, je m'appelle David.", BingSpeech.SupportedLocales.frFR_Female);
bingClientTTS.synthesize("Hallo, mein Name ist Frank.", BingSpeech.SupportedLocales.deDE_Male);
bingClientTTS.synthesize("Zdravstvuite, menya zovut Kristina i ya rada vas privetstvovat'", BingSpeech.SupportedLocales.ruRU_Female);

Callback

// If you need a block of text to be read/speech before continuing, you can use the optional callback
// This code will download & play the 3 first sentences 
// Once the 3 sentences will be speech a new final XHR will be launched
// to download & play the last sentence using EN-GB Female.
bingClientTTS.synthesize("Hallo, mein Name ist Frank.", BingSpeech.SupportedLocales.deDE_Male);
bingClientTTS.synthesize("Wie geht es Ihnen?", BingSpeech.SupportedLocales.deDE_Female);
bingClientTTS.synthesize("Zdravstvuite, menya zovut Kristina i ya rada vas privetstvovat'"
    , BingTTS.SupportedLocales.ruRU_Female
    , () => {
        bingClientTTS.synthesize("Even more later text to speech!", BingSpeech.SupportedLocales.enGB_Female);
    }); 

By default, the library is sending multiple XHR in parallel to have better performance. But your text will be speech in the order of the calls to synthetize().

Still, if you’d like to serialize them to have a unique XHR being processed in background, you can change this flag to:

bingClientTTS.multipleXHR = false;

It can be useful for the free version of your Bing Speech account to avoid reaching the quota of number of requests / min too quickly.