Castor/anserini_dependency/js/speech.js

/*
Modifications Copyright 2017 Anserini

The audio recording and analyzer visualization code was originally developed by Chris Wilson
and modified for use in Anserini.

Copyright 2013 Chris Wilson

 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.
 */

window.AudioContext = window.AudioContext || window.webkitAudioContext;

var audioContext = new AudioContext();
var audioInput = null,
  realAudioInput = null,
  inputPoint = null,
  audioRecorder = null;
var rafID = null;
var analyserContext = null;
var canvasWidth, canvasHeight;
var recIndex = 0;

function saveAudio() {
  //audioRecorder.exportWAV( doneEncoding );
  // could get mono instead by saying
   audioRecorder.exportMonoWAV( doneEncoding );
}

function gotBuffers(buffers) {
  // the ONLY time gotBuffers is called is right after a new recording is completed.
  audioRecorder.exportMonoWAV( doneEncoding );
}

function doneEncoding(blob) {
  Recorder.speechToText(blob);
  recIndex++;
}

function toggleRecording(e) {
  if (e.classList.contains("recording")) {
    // stop recording
    audioRecorder.stop();
    e.classList.remove("recording");
    $('#question').text("Trying to understand your query...");
    audioRecorder.getBuffers( gotBuffers );
  } else {
    // start recording
    if (!audioRecorder)
      return;
    e.classList.add("recording");
    $('#question').text("Listening...");
    $('#answer').html("");
    audioRecorder.clear();
    audioRecorder.record();
  }
}

function convertToMono(input) {
  var splitter = audioContext.createChannelSplitter(2);
  var merger = audioContext.createChannelMerger(2);

  input.connect(splitter);
  splitter.connect(merger, 0, 0);
  splitter.connect(merger, 0, 1);
  return merger;
}

function cancelAnalyserUpdates() {
  window.cancelAnimationFrame(rafID);
  rafID = null;
}

function updateAnalysers(time) {
  if (!analyserContext) {
    var canvas = document.getElementById("analyser");
    canvasWidth = canvas.width;
    canvasHeight = canvas.height;
    analyserContext = canvas.getContext('2d');
  }

  // analyzer draw code here
  {
    var SPACING = 5;
    var BAR_WIDTH = 3;
    var numBars = Math.round(canvasWidth / SPACING);
    var freqByteData = new Uint8Array(analyserNode.frequencyBinCount);

    analyserNode.getByteFrequencyData(freqByteData);

    analyserContext.clearRect(0, 0, canvasWidth, canvasHeight);
    analyserContext.fillStyle = '#F6D565';
    analyserContext.lineCap = 'round';
    var multiplier = analyserNode.frequencyBinCount / numBars;

    // Draw rectangle for each frequency bin.
    for (var i = 0; i < numBars; ++i) {
      var magnitude = 0;
      var offset = Math.floor( i * multiplier );
      // gotta sum/average the block, or we miss narrow-bandwidth spikes
      for (var j = 0; j< multiplier; j++)
        magnitude += freqByteData[offset + j];
      magnitude = magnitude / multiplier;
      var magnitude2 = freqByteData[i * multiplier];
      analyserContext.fillStyle = "hsl( " + Math.round((i*360)/numBars) + ", 100%, 50%)";
      analyserContext.fillRect(i * SPACING, canvasHeight, BAR_WIDTH, -magnitude);
    }
  }

  rafID = window.requestAnimationFrame(updateAnalysers);
}

function toggleMono() {
  if (audioInput != realAudioInput) {
    audioInput.disconnect();
    realAudioInput.disconnect();
    audioInput = realAudioInput;
  } else {
    realAudioInput.disconnect();
    audioInput = convertToMono( realAudioInput );
  }

  audioInput.connect(inputPoint);
}

function gotStream(stream) {
  inputPoint = audioContext.createGain();

  // Create an AudioNode from the stream.
  realAudioInput = audioContext.createMediaStreamSource(stream);
  audioInput = realAudioInput;
  audioInput.connect(inputPoint);

  analyserNode = audioContext.createAnalyser();
  analyserNode.fftSize = 2048;
  inputPoint.connect( analyserNode );

  audioRecorder = new Recorder( inputPoint );

  zeroGain = audioContext.createGain();
  zeroGain.gain.value = 0.0;
  inputPoint.connect( zeroGain );
  zeroGain.connect( audioContext.destination );
  updateAnalysers();
}

function initAudio() {
  if (!navigator.getUserMedia)
    navigator.getUserMedia = navigator.webkitGetUserMedia || navigator.mozGetUserMedia;
  if (!navigator.cancelAnimationFrame)
    navigator.cancelAnimationFrame = navigator.webkitCancelAnimationFrame || navigator.mozCancelAnimationFrame;
  if (!navigator.requestAnimationFrame)
    navigator.requestAnimationFrame = navigator.webkitRequestAnimationFrame || navigator.mozRequestAnimationFrame;

  navigator.getUserMedia(
    {
      "audio": {
        "mandatory": {
          "googEchoCancellation": "false",
          "googAutoGainControl": "false",
          "googNoiseSuppression": "false",
          "googHighpassFilter": "false"
        },
        "optional": []
      }
    }, gotStream, function(e) {
      alert('Error getting audio');
      console.log(e);
    });
}

window.addEventListener('load', initAudio);