Source: recognize-microphone.js

'use strict';

/**
 * Copyright 2015 IBM Corp. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

'use strict';
var getUserMedia = require('./getusermedia');
var MicrophoneStream = require('microphone-stream');
var RecognizeStream = require('./recognize-stream.js');
var L16 = require('./webaudio-l16-stream.js');
var FormatStream = require('./format-stream.js');

/**
 * Create and return a RecognizeStream from the user's microphone
 * If the options.file is set, it is used instead of the microphone
 *
 * @param {Object} options - Also passed to {MediaElementAudioStream} and to {RecognizeStream}
 * @param {String} options.token - Auth Token - see https://github.com/watson-developer-cloud/node-sdk#authorization
 * @param {Boolena} [options.format=true] - pipe the text through a {FormatStream} which performs light formatting
 *
 * @returns {RecognizeStream}
 */
module.exports = function recognizeMicrophone(options) {
  if (!options || !options.token) {
    throw new Error("WatsonSpeechToText: missing required parameter: opts.token");
  }

  options['content-type'] = 'audio/l16;rate=16000'; // raw wav audio (no header)
  var recognizeStream = new RecognizeStream(options);

  getUserMedia({video: false, audio: true}).then(function(mic) {
    var micStream = new MicrophoneStream(mic, {
      objectMode: true,
      bufferSize: options.bufferSize
    });
    micStream
      .pipe(new L16())
      .pipe(recognizeStream);

    recognizeStream.on('stop', micStream.stop.bind(micStream));
  }).catch(recognizeStream.emit.bind(recognizeStream, 'error'));


  var stream = recognizeStream;
  if (options.format !== false) {
    stream = stream.pipe(new FormatStream(options));
  }

  return stream;
};