Access microphone from a browser - Javascript

Question

Is it possible to access the microphone (built-in or auxiliary) from a browser using client-side JavaScript?

Ideally, it would store the recorded audio in the browser. Thanks!

@poisonlocc Check this out: http://www.html5rocks.com/en/tutorials/getusermedia/intro/ — Brad, Jan 08 '15 at 17:52

Scott Stensland · Answer 1 · 2019-12-18T11:41:37.520

Here we capture microphone audio as a Web Audio API event loop buffer using getUserMedia() ... time domain and frequency domain snippets of each audio event loop buffer are printed (viewable in browser console just hit key F12 or ctrl+shift+i )

<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>capture microphone audio into buffer</title>

<script type="text/javascript">


  var webaudio_tooling_obj = function () {

    var audioContext = new AudioContext();

    console.log("audio is starting up ...");

    var BUFF_SIZE = 16384;

    var audioInput = null,
        microphone_stream = null,
        gain_node = null,
        script_processor_node = null,
        script_processor_fft_node = null,
        analyserNode = null;

    if (!navigator.getUserMedia)
            navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia ||
                          navigator.mozGetUserMedia || navigator.msGetUserMedia;

    if (navigator.getUserMedia){

        navigator.getUserMedia({audio:true}, 
          function(stream) {
              start_microphone(stream);
          },
          function(e) {
            alert('Error capturing audio.');
          }
        );

    } else { alert('getUserMedia not supported in this browser.'); }

    // ---

    function show_some_data(given_typed_array, num_row_to_display, label) {

        var size_buffer = given_typed_array.length;
        var index = 0;
        var max_index = num_row_to_display;

        console.log("__________ " + label);

        for (; index < max_index && index < size_buffer; index += 1) {

            console.log(given_typed_array[index]);
        }
    }

    function process_microphone_buffer(event) { // invoked by event loop

        var i, N, inp, microphone_output_buffer;

        microphone_output_buffer = event.inputBuffer.getChannelData(0); // just mono - 1 channel for now

        // microphone_output_buffer  <-- this buffer contains current gulp of data size BUFF_SIZE

        show_some_data(microphone_output_buffer, 5, "from getChannelData");
    }

    function start_microphone(stream){

      gain_node = audioContext.createGain();
      gain_node.connect( audioContext.destination );

      microphone_stream = audioContext.createMediaStreamSource(stream);
      microphone_stream.connect(gain_node); 

      script_processor_node = audioContext.createScriptProcessor(BUFF_SIZE, 1, 1);
      script_processor_node.onaudioprocess = process_microphone_buffer;

      microphone_stream.connect(script_processor_node);

      // --- enable volume control for output speakers

      document.getElementById('volume').addEventListener('change', function() {

          var curr_volume = this.value;
          gain_node.gain.value = curr_volume;

          console.log("curr_volume ", curr_volume);
      });

      // --- setup FFT

      script_processor_fft_node = audioContext.createScriptProcessor(2048, 1, 1);
      script_processor_fft_node.connect(gain_node);

      analyserNode = audioContext.createAnalyser();
      analyserNode.smoothingTimeConstant = 0;
      analyserNode.fftSize = 2048;

      microphone_stream.connect(analyserNode);

      analyserNode.connect(script_processor_fft_node);

      script_processor_fft_node.onaudioprocess = function() {

        // get the average for the first channel
        var array = new Uint8Array(analyserNode.frequencyBinCount);
        analyserNode.getByteFrequencyData(array);

        // draw the spectrogram
        if (microphone_stream.playbackState == microphone_stream.PLAYING_STATE) {

            show_some_data(array, 5, "from fft");
        }
      };
    }

  }(); //  webaudio_tooling_obj = function()



</script>

</head>
<body>

    <p>Volume</p>
    <input id="volume" type="range" min="0" max="1" step="0.1" value="0.5"/>

</body>
</html>

Since this code exposes microphone data as a buffer you could add ability to stream using websockets or simply aggregate each event loop buffer into a monster buffer then download the monster to a file

Notice the call to

    var audioContext = new AudioContext();

which indicates its using the Web Audio API which is baked into all modern browsers (including mobile browsers) to provide an extremely powerful audio platform of which tapping into the mic is but a tiny fragment ... NOTE the CPU usage jumps up due to this demo writing each event loop buffer into browser console log which is for testing only so actual use is far less resource intensive even when you mod this to stream audio to elsewhere

Links to some Web Audio API documentation

Hi @scott-stensland, this is great. Did you write this code? Is there an original source or repo or license for it? Thanks! — binarymax, Aug 11 '16 at 18:31
@binarymax Yes its my code ... feel free to pillage at will ... I taught myself above tricks while writing https://github.com/scottstensland/websockets-streaming-audio which streams audio from the server using websockets to then render in the browser using Web Audio API using a webworker interstitial layer in-between to babysit the network traffic ... I need to reactor that code ;-) as it was strictly a learning exercise — Scott Stensland, Aug 11 '16 at 20:05
What is a good way to learn all this, i Know javascritp and dom. I dont know audio api and everything that goes with it like buffer size, channels, stream etc — Muhammad Umer, Jun 13 '17 at 22:23
Note that now [MDN](https://developer.mozilla.org/en-US/docs/Web/API/Navigator/getUserMedia) recommends using "the newer `navigator.mediaDevices.getUserMedia()` instead" — RyanQuey, Feb 24 '19 at 15:17

score 4 · Answer 2 · edited Feb 22 '21 at 16:29

4

Yes you can.

Using the getUserMedia() API, you can capture raw audio input from your microphone.

edited Feb 22 '21 at 16:29

luk2302

46,204
19
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answered Jan 08 '15 at 17:49

user2879041

1,031
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I know linking another URL is bad, but it looks like this is the new place: https://ulistentome.wordpress.com/2014/10/24/recording-mp3-using-only-html5-and-javascript-recordmp3-js/ – Norbert Jun 10 '20 at 07:45

Access microphone from a browser - Javascript

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